Apparatus for transmitting broadcast signals, apparatus for receiving broadcast signals, method for transmitting broadcast signals and method for receiving broadcast signals

ABSTRACT

The present invention provides a method of transmitting broadcast signals. The method includes encoding service data of Physical Layer Pipes (PLPs); bit interleaving the encoded service data; building at least one signal frame including the bit interleaved service data; and modulating data in the at least one signal frame by Orthogonal Frequency Division Multiplexing (OFDM) method; inserting a preamble at a beginning of each of the at least one signal frame after the modulating step; and transmitting the broadcast signals having the modulated data, wherein the preamble includes information for a size of Fast Fourier Transform (FFT), a guard interval and a pilot mode, wherein the preamble includes two OFDM symbols, and wherein each of the two OFDM symbols in the preamble includes information for an emergency alert.

This application claims the benefit of U.S. Provisional Application No.61/908,693 filed on Nov. 25, 2013, U.S. Provisional Application No.61/908,722 filed on Nov. 25, 2013, which is hereby incorporated byreference as if fully set forth herein.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to an apparatus for transmitting broadcastsignals, an apparatus for receiving broadcast signals and methods fortransmitting and receiving broadcast signals.

Discussion of the Related Art

As analog broadcast signal transmission comes to an end, varioustechnologies for transmitting/receiving digital broadcast signals arebeing developed. A digital broadcast signal may include a larger amountof video/audio data than an analog broadcast signal and further includevarious types of additional data in addition to the video/audio data.

That is, a digital broadcast system can provide HD (high definition)images, multi-channel audio and various additional services. However,data transmission efficiency for transmission of large amounts of data,robustness of transmission/reception networks and network flexibility inconsideration of mobile reception equipment need to be improved fordigital broadcast.

SUMMARY OF THE INVENTION

Accordingly, the present invention is directed to an apparatus fortransmitting broadcast signals and an apparatus for receiving broadcastsignals for future broadcast services and methods for transmitting andreceiving broadcast signals for future broadcast services.

An object of the present invention is to provide an apparatus and methodfor transmitting broadcast signals to multiplex data of a broadcasttransmission/reception system providing two or more different broadcastservices in a time domain and transmit the multiplexed data through thesame RF signal bandwidth and an apparatus and method for receivingbroadcast signals corresponding thereto.

Another object of the present invention is to provide an apparatus fortransmitting broadcast signals, an apparatus for receiving broadcastsignals and methods for transmitting and receiving broadcast signals toclassify data corresponding to services by components, transmit datacorresponding to each component as a data pipe, receive and process thedata

Still another object of the present invention is to provide an apparatusfor transmitting broadcast signals, an apparatus for receiving broadcastsignals and methods for transmitting and receiving broadcast signals tosignal signaling information necessary to provide broadcast signals.

To achieve the object and other advantages and in accordance with thepurpose of the invention, as embodied and broadly described herein, thepresent invention provides a method of transmitting broadcast signals.The method of transmitting broadcast signals includes demultiplexinginput streams into plural PLPs (Physical Layer Pipes); encoding data ofthe each PLPs according to each physical layer profiles, wherein thephysical layer profiles are configurations based on reception condition,wherein the each physical layer profiles include: LDPC (Low DensityParity Check) encoding the data of the PLP, bit interleaving the LDPCencoded data of the PLP; building plural signal frames by mapping theencoded data of the each PLPs, wherein each signal frame belongs to oneof the physical layer profiles, wherein a super frame includes at leasttwo built signal frames; and modulating data in the built plural signalframes by OFDM (Orthogonal Frequency Division Multiplexing) method andtransmitting the broadcast signals having the modulated data, wherein apreamble of the signal frame includes a first signal field indicatingtype of the current signal frame.

Preferably, the preamble further includes a second signal fieldindicating whether data encoded for fixed reception are present in thecurrent super frame, or not.

Preferably, the preamble further includes a second signal fieldindicating configuration of the physical layer profiles of the signalframes in the super frame

Preferably, value of the second signal field indicates whether a signalframe of certain physical layer profile is present in the super frame,in combination with value of the first signal field.

Preferably, the physical layer profiles include a first physical layerprofile, a second physical layer profile, and a third physical layerprofile, when the first signal field indicates that the current signalframe is a signal frame of the first physical layer profile, whereinfirst bit of the second signal field indicates whether a signal frame ofthe second physical layer profile is present in the super frame,

wherein second bit of the second signal field indicates whether a signalframe of the third physical layer profile is present in the super frame,and wherein third bit of the second signal field indicates whether FEF(Future Extension Frame) is present in the super frame.

Preferably, one of the physical layer profile further includes: mappingthe bit interleaved data of the PLP onto constellations, MIMO (MultiInput Multi Output) encoding the mapped data, and time interleaving theMIMO encoded data.

In other aspect, the present invention provides a method of receivingbroadcast signals. The method of receiving broadcast signals includesreceiving the broadcast signals having plural signal frames anddemodulating data in the plural signal frames by OFDM (OrthogonalFrequency Division Multiplexing) method; parsing the plural signalframes by demapping data of plural PLPs (Physical Layer Pipes), whereineach signal frame belongs to one of physical layer profiles, wherein thephysical layer profiles are configurations based on reception condition,wherein a super frame includes at least two signal frames; decoding thedata of the each PLPs according to the each physical layer profiles,wherein the each physical layer profiles include: bit deinterleaving thedata of the PLP, LDPC (Low Density Parity Check) decoding the bitdeinterleaved data of the PLP; and multiplexing the decoded plural PLPsinto output streams, wherein a preamble of the signal frame includes afirst signal field indicating type of the current signal frame.

Preferably, the preamble further includes a second signal fieldindicating whether data encoded for fixed reception are present in thecurrent super frame, or not.

Preferably, the preamble further includes a second signal fieldindicating configuration of the physical layer profiles of the signalframes in the super frame

Preferably, value of the second signal field indicates whether a signalframe of certain physical layer profile is present in the super frame,in combination with value of the first signal field.

Preferably, the physical layer profiles include a first physical layerprofile, a second physical layer profile, and a third physical layerprofile, when the first signal field indicates that the current signalframe is a signal frame of the first physical layer profile, whereinfirst bit of the second signal field indicates whether a signal frame ofthe second physical layer profile is present in the super frame,

wherein second bit of the second signal field indicates whether a signalframe of the third physical layer profile is present in the super frame,and wherein third bit of the second signal field indicates whether FEF(Future Extension Frame) is present in the super frame.

Preferably, one of the physical layer profile further includes: timedeinterleaving the data of the PLP, MIMO (Multi Input Multi Output)decoding the time deinterleaved data, and demapping the MIMO decodeddata from constellations for bit deinterleaving.

In another aspect, the present invention provides an apparatus fortransmitting broadcast signals. The apparatus for transmitting broadcastsignals includes a demultiplexing module to demultiplex input streamsinto plural PLPs (Physical Layer Pipes); an encoding module to encodedata of the each PLPs according to each physical layer profiles, whereinthe physical layer profiles are configurations based on receptioncondition, wherein the each physical layer profiles include: an LDPC(Low Density Parity Check) encoding module to LDPC encode the data ofthe PLP, a bit interleaving module to bit interleave the LDPC encodeddata of the PLP; a frame building module to build plural signal framesby mapping the encoded data of the each PLPs, wherein each signal framebelongs to one of the physical layer profiles, wherein a super frameincludes at least two built signal frames; and an OFDM module tomodulate data in the built plural signal frames by OFDM (OrthogonalFrequency Division Multiplexing) method and to transmit the broadcastsignals having the modulated data, wherein a preamble of the signalframe includes a first signal field indicating type of the currentsignal frame.

Preferably, the preamble further includes a second signal fieldindicating whether data encoded for fixed reception are present in thecurrent super frame, or not.

Preferably, the preamble further includes a second signal fieldindicating configuration of the physical layer profiles of the signalframes in the super frame

Preferably, value of the second signal field indicates whether a signalframe of certain physical layer profile is present in the super frame,in combination with value of the first signal field.

Preferably, the physical layer profiles include a first physical layerprofile, a second physical layer profile, and a third physical layerprofile, when the first signal field indicates that the current signalframe is a signal frame of the first physical layer profile, whereinfirst bit of the second signal field indicates whether a signal frame ofthe second physical layer profile is present in the super frame,

wherein second bit of the second signal field indicates whether a signalframe of the third physical layer profile is present in the super frame,and wherein third bit of the second signal field indicates whether FEF(Future Extension Frame) is present in the super frame.

Preferably, one of the physical layer profile further includes: amapping module to map the bit interleaved data of the PLP ontoconstellations, a MIMO (Multi Input Multi Output) encoding module toMIMO encode the mapped data, and a time interleaving module to timeinterleave the MIMO encoded data.

In another aspect, the present invention provides an apparatus forreceiving broadcast signals. The apparatus for receiving broadcastsignals includes a receiving module to receive the broadcast signalshaving plural signal frames and to demodulate data in the plural signalframes by OFDM (Orthogonal Frequency Division Multiplexing) method; aparsing module to parse the plural signal frames by demapping data ofplural PLPs (Physical Layer Pipes), wherein each signal frame belongs toone of physical layer profiles, wherein the physical layer profiles areconfigurations based on reception condition, wherein a super frameincludes at least two signal frames; a decoding module to decode thedata of the each PLPs according to the each physical layer profiles,wherein the each physical layer profiles include: a bit deinterleavingmodule to bit deinterleave the data of the PLP, an LDPC (Low DensityParity Check) decoding module to LDPC decode the bit deinterleaved dataof the PLP; and a multiplexing module to multiplex the decoded pluralPLPs into output streams, wherein a preamble of the signal frameincludes a first signal field indicating type of the current signalframe.

Preferably, the preamble further includes a second signal fieldindicating whether data encoded for fixed reception are present in thecurrent super frame, or not.

Preferably, the preamble further includes a second signal fieldindicating configuration of the physical layer profiles of the signalframes in the super frame

Preferably, value of the second signal field indicates whether a signalframe of certain physical layer profile is present in the super frame,in combination with value of the first signal field.

Preferably, the physical layer profiles include a first physical layerprofile, a second physical layer profile, and a third physical layerprofile, when the first signal field indicates that the current signalframe is a signal frame of the first physical layer profile, whereinfirst bit of the second signal field indicates whether a signal frame ofthe second physical layer profile is present in the super frame,

wherein second bit of the second signal field indicates whether a signalframe of the third physical layer profile is present in the super frame,and wherein third bit of the second signal field indicates whether FEF(Future Extension Frame) is present in the super frame.

Preferably, one of the physical layer profile further includes: a timedeinterleaving module to time deinterleave the data of the PLP, a MIMO(Multi Input Multi Output) decoding module to MIMO decode the timedeinterleaved data, and a demapping module to demap the MIMO decodeddata from constellations for bit deinterleaving.

The present invention can process data according to servicecharacteristics to control QoS (Quality of Services) for each service orservice component, thereby providing various broadcast services.

The present invention can achieve transmission flexibility bytransmitting various broadcast services through the same RF signalbandwidth.

The present invention can improve data transmission efficiency andincrease robustness of transmission/reception of broadcast signals usinga MIMO system.

According to the present invention, it is possible to provide broadcastsignal transmission and reception methods and apparatus capable ofreceiving digital broadcast signals without error even with mobilereception equipment or in an indoor environment.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this application, illustrate embodiment(s) of the invention andtogether with the description serve to explain the principle of theinvention. In the drawings:

FIG. 1 illustrates a structure of an apparatus for transmittingbroadcast signals for future broadcast services according to anembodiment of the present invention.

FIG. 2 illustrates an input formatting block according to one embodimentof the present invention.

FIG. 3 illustrates an input formatting block according to anotherembodiment of the present invention.

FIG. 4 illustrates an input formatting block according to anotherembodiment of the present invention.

FIG. 5 illustrates a BICM block according to an embodiment of thepresent invention.

FIG. 6 illustrates a BICM block according to another embodiment of thepresent invention.

FIG. 7 illustrates a frame building block according to one embodiment ofthe present invention.

FIG. 8 illustrates an OFMD generation block according to an embodimentof the present invention.

FIG. 9 illustrates a structure of an apparatus for receiving broadcastsignals for future broadcast services according to an embodiment of thepresent invention.

FIG. 10 illustrates a frame structure according to an embodiment of thepresent invention.

FIG. 11 illustrates a signaling hierarchy structure of the frameaccording to an embodiment of the present invention.

FIG. 12 illustrates preamble signaling data according to an embodimentof the present invention.

FIG. 13 illustrates PLS1 data according to an embodiment of the presentinvention.

FIG. 14 illustrates PLS2 data according to an embodiment of the presentinvention.

FIG. 15 illustrates PLS2 data according to another embodiment of thepresent invention.

FIG. 16 illustrates a logical structure of a frame according to anembodiment of the present invention.

FIG. 17 illustrates PLS mapping according to an embodiment of thepresent invention.

FIG. 18 illustrates EAC mapping according to an embodiment of thepresent invention.

FIG. 19 illustrates FIC mapping according to an embodiment of thepresent invention.

FIG. 20 illustrates a type of DP according to an embodiment of thepresent invention.

FIG. 21 illustrates DP mapping according to an embodiment of the presentinvention.

FIG. 22 illustrates an FEC structure according to an embodiment of thepresent invention.

FIG. 23 illustrates a bit interleaving according to an embodiment of thepresent invention.

FIG. 24 illustrates a cell-word demultiplexing according to anembodiment of the present invention.

FIG. 25 illustrates a time interleaving according to an embodiment ofthe present invention.

FIG. 26 illustrates the basic operation of a twisted row-column blockinterleaver according to an embodiment of the present invention.

FIG. 27 illustrates an operation of a twisted row-column blockinterleaver according to another embodiment of the present invention.

FIG. 28 illustrates a diagonal-wise reading pattern of a twistedrow-column block interleaver according to an embodiment of the presentinvention.

FIG. 29 illustrates interlaved XFECBLOCKs from each interleaving arrayaccording to an embodiment of the present invention.

FIG. 30 illustrates a frame structure of a broadcast system according toan embodiment of the present invention.

FIG. 31 illustrates a preamble insertion block according to anembodiment of the present invention.

FIG. 32 shows mathematical expressions representing relationshipsbetween input information and output information or mapping rules of theDQPSK/DBPSK mapper 17040 according to an embodiment of the presentinvention.

FIG. 33 illustrates preamble structures according to an embodiment ofthe present invention.

FIG. 34 illustrates a preamble insertion block according to anembodiment of the present invention.

FIG. 35 illustrates a preamble insertion block according to anembodiment of the present invention.

FIG. 36 is a graph showing a scrambling sequence according to anembodiment of the present invention.

FIG. 37 illustrates examples of scrambling sequences modified from thebinary chirp-like sequence according to an embodiment of the presentinvention.

FIG. 38 illustrates a signaling information structure in the preambleaccording to an embodiment of the present invention.

FIG. 39 illustrates a procedure of processing signaling data transmittedthrough the preamble according to an embodiment of the presentinvention.

FIG. 40 illustrates a procedure of processing signaling data transmittedthrough the preamble according to an embodiment of the presentinvention.

FIG. 41 illustrates a differential encoding operation that can beperformed by a preamble insertion module according to an embodiment ofthe present invention.

FIG. 42 illustrates a differential encoding operation that can beperformed by a preamble insertion module according to another embodimentof the present invention.

FIG. 43 is a block diagram of a correlation detector included in apreamble detector according to an embodiment of the present invention.

FIG. 44 illustrates a signaling decoder of a preamble detector accordingto an embodiment of the present invention.

FIG. 45 illustrates a signaling decoder of a preamble detector accordingto an embodiment of the present invention.

FIG. 46 illustrates a signaling decoder of a preamble detector accordingto an embodiment of the present invention.

FIG. 47 shows an OFDM generation block according to another embodimentof the present invention.

FIG. 48 shows a synchronization & demodulation module according to oneembodiment of the present invention.

FIG. 49 illustrates a signal frame and a preamble structure thereofaccording to the conventional art.

FIG. 50 illustrates a conventional channel scanning process.

FIG. 51 illustrates a problem of the conventional channel scanningprocess.

FIG. 52 illustrates a signal frame and a preamble structure thereofaccording to one embodiment of the present invention.

FIG. 53 illustrates a signaling format of FRU_CONFIGURE of a preambleaccording to one embodiment of the present invention.

FIG. 54 illustrates a channel scanning process using preamble signalingaccording to one embodiment of the present invention.

FIG. 55 illustrates preamble signaling according to one embodiment ofthe present invention.

FIG. 56 illustrates a method of transmitting broadcast signal accordingto an embodiment of the present invention.

FIG. 57 illustrates a method of receiving broadcast signal according toan embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in detail to the preferred embodiments of thepresent invention, examples of which are illustrated in the accompanyingdrawings. The detailed description, which will be given below withreference to the accompanying drawings, is intended to explain exemplaryembodiments of the present invention, rather than to show the onlyembodiments that can be implemented according to the present invention.The following detailed description includes specific details in order toprovide a thorough understanding of the present invention. However, itwill be apparent to those skilled in the art that the present inventionmay be practiced without such specific details.

Although most terms used in the present invention have been selectedfrom general ones widely used in the art, some terms have beenarbitrarily selected by the applicant and their meanings are explainedin detail in the following description as needed. Thus, the presentinvention should be understood based upon the intended meanings of theterms rather than their simple names or meanings.

The present invention provides apparatuses and methods for transmittingand receiving broadcast signals for future broadcast services. Futurebroadcast services according to an embodiment of the present inventioninclude a terrestrial broadcast service, a mobile broadcast service, aUHDTV service, etc. The present invention may process broadcast signalsfor the future broadcast services through non-MIMO (Multiple InputMultiple Output) or MIMO according to one embodiment. A non-MIMO schemeaccording to an embodiment of the present invention may include a MISO(Multiple Input Single Output) scheme, a SISO (Single Input SingleOutput) scheme, etc.

While MISO or MIMO uses two antennas in the following for convenience ofdescription, the present invention is applicable to systems using two ormore antennas.

The present invention may defines three physical layer (PL)profiles—base, handheld and advanced profiles—each optimized to minimizereceiver complexity while attaining the performance required for aparticular use case. The physical layer (PHY) profiles are subsets ofall configurations that a corresponding receiver should implement.

The three PHY profiles share most of the functional blocks but differslightly in specific blocks and/or parameters. Additional PHY profilescan be defined in the future. For the system evolution, future profilescan also be multiplexed with the existing profiles in a single RFchannel through a future extension frame (FEF). The details of each PHYprofile are described below.

1. Base Profile

The base profile represents a main use case for fixed receiving devicesthat are usually connected to a roof-top antenna. The base profile alsoincludes portable devices that could be transported to a place butbelong to a relatively stationary reception category. Use of the baseprofile could be extended to handheld devices or even vehicular by someimproved implementations, but those use cases are not expected for thebase profile receiver operation.

Target SNR range of reception is from approximately 10 to 20 dB, whichincludes the 15 dB SNR reception capability of the existing broadcastsystem (e.g. ATSC A/53). The receiver complexity and power consumptionis not as critical as in the battery-operated handheld devices, whichwill use the handheld profile. Key system parameters for the baseprofile are listed in below table 1.

TABLE 1 LDPC codeword length 16K, 64K bits Constellation size 4~10 bpcu(bits per channel use) Time de-interleaving memory size ≦2¹⁹ data cellsPilot patterns Pilot pattern for fixed reception FFT size 16K, 32Kpoints

2. Handheld Profile

The handheld profile is designed for use in handheld and vehiculardevices that operate with battery power. The devices can be moving withpedestrian or vehicle speed. The power consumption as well as thereceiver complexity is very important for the implementation of thedevices of the handheld profile. The target SNR range of the handheldprofile is approximately 0 to 10 dB, but can be configured to reachbelow 0 dB when intended for deeper indoor reception.

In addition to low SNR capability, resilience to the Doppler Effectcaused by receiver mobility is the most important performance attributeof the handheld profile. Key system parameters for the handheld profileare listed in the below table 2.

TABLE 2 LDPC codeword length 16K bits Constellation size 2~8 bpcu Timede-interleaving memory size ≦2¹⁸ data cells Pilot patterns Pilotpatterns for mobile and indoor reception FFT size 8K, 16K points

3. Advanced Profile

The advanced profile provides highest channel capacity at the cost ofmore implementation complexity. This profile requires using MIMOtransmission and reception, and UHDTV service is a target use case forwhich this profile is specifically designed. The increased capacity canalso be used to allow an increased number of services in a givenbandwidth, e.g., multiple SDTV or HDTV services.

The target SNR range of the advanced profile is approximately 20 to 30dB. MIMO transmission may initially use existing elliptically-polarizedtransmission equipment, with extension to full-power cross-polarizedtransmission in the future. Key system parameters for the advancedprofile are listed in below table 3.

TABLE 3 LDPC codeword length 16K, 64K bits Constellation size 8~12 bpcuTime de-interleaving memory size ≦2¹⁹ data cells Pilot patterns Pilotpattern for fixed reception FFT size 16K, 32K points

In this case, the base profile can be used as a profile for both theterrestrial broadcast service and the mobile broadcast service. That is,the base profile can be used to define a concept of a profile whichincludes the mobile profile. Also, the advanced profile can be dividedadvanced profile for a base profile with MIMO and advanced profile for ahandheld profile with MIMO. Moreover, the three profiles can be changedaccording to intention of the designer.

The following terms and definitions may apply to the present invention.The following terms and definitions can be changed according to design.

auxiliary stream: sequence of cells carrying data of as yet undefinedmodulation and coding, which may be used for future extensions or asrequired by broadcasters or network operators

base data pipe: data pipe that carries service signaling data

baseband frame (or BBFRAME): set of K_(bch) bits which form the input toone FEC encoding process (BCH and LDPC encoding)

cell: modulation value that is carried by one carrier of the OFDMtransmission

coded block: LDPC-encoded block of PLS1 data or one of the LDPC-encodedblocks of PLS2 data

data pipe: logical channel in the physical layer that carries servicedata or related metadata, which may carry one or multiple service(s) orservice component(s).

data pipe unit: a basic unit for allocating data cells to a DP in aframe.

data symbol: OFDM symbol in a frame which is not a preamble symbol (theframe signaling symbol and frame edge symbol is included in the datasymbol)

DP_ID: this 8-bit field identifies uniquely a DP within the systemidentified by the SYSTEM_ID

dummy cell: cell carrying a pseudo-random value used to fill theremaining capacity not used for PLS signaling, DPs or auxiliary streams

emergency alert channel: part of a frame that carries EAS informationdata

frame: physical layer time slot that starts with a preamble and endswith a frame edge symbol

frame repetition unit: a set of frames belonging to same or differentphysical layer profile including a FEF, which is repeated eight times ina super-frame

fast information channel: a logical channel in a frame that carries themapping information between a service and the corresponding base DP

FECBLOCK: set of LDPC-encoded bits of a DP data

FFT size: nominal FFT size used for a particular mode, equal to theactive symbol period T_(S) expressed in cycles of the elementary periodT

frame signaling symbol: OFDM symbol with higher pilot density used atthe start of a frame in certain combinations of FFT size, guard intervaland scattered pilot pattern, which carries a part of the PLS data

frame edge symbol: OFDM symbol with higher pilot density used at the endof a frame in certain combinations of FFT size, guard interval andscattered pilot pattern

frame-group: the set of all the frames having the same PHY profile typein a super-frame.

future extension frame: physical layer time slot within the super-framethat could be used for future extension, which starts with a preamble

Futurecast UTB system: proposed physical layer broadcasting system, ofwhich the input is one or more MPEG2-TS or IP or general stream(s) andof which the output is an RF signal

input stream: A stream of data for an ensemble of services delivered tothe end users by the system.

normal data symbol: data symbol excluding the frame signaling symbol andthe frame edge symbol

PHY profile: subset of all configurations that a corresponding receivershould implement

PLS: physical layer signaling data consisting of PLS1 and PLS2

PLS1: a first set of PLS data carried in the FSS symbols having a fixedsize, coding and modulation, which carries basic information about thesystem as well as the parameters needed to decode the PLS2

NOTE: PLS1 data remains constant for the duration of a frame-group.

PLS2: a second set of PLS data transmitted in the FSS symbol, whichcarries more detailed PLS data about the system and the DPs

PLS2 dynamic data: PLS2 data that may dynamically change frame-by-frame

PLS2 static data: PLS2 data that remains static for the duration of aframe-group

preamble signaling data: signaling data carried by the preamble symboland used to identify the basic mode of the system

preamble symbol: fixed-length pilot symbol that carries basic PLS dataand is located in the beginning of a frame

NOTE: The preamble symbol is mainly used for fast initial band scan todetect the system signal, its timing, frequency offset, and FFT-size.

reserved for future use: not defined by the present document but may bedefined in future

super-frame: set of eight frame repetition units

time interleaving block (TI block): set of cells within which timeinterleaving is carried out, corresponding to one use of the timeinterleaver memory

TI group: unit over which dynamic capacity allocation for a particularDP is carried out, made up of an integer, dynamically varying number ofXFECBLOCKs.

NOTE: The TI group may be mapped directly to one frame or may be mappedto multiple frames. It may contain one or more TI blocks.

Type 1 DP: DP of a frame where all DPs are mapped into the frame in TDMfashion

Type 2 DP: DP of a frame where all DPs are mapped into the frame in FDMfashion

XFECBLOCK: set of N cells cells carrying all the bits of one LDPCFECBLOCK

FIG. 1 illustrates a structure of an apparatus for transmittingbroadcast signals for future broadcast services according to anembodiment of the present invention.

The apparatus for transmitting broadcast signals for future broadcastservices according to an embodiment of the present invention can includean input formatting block 1000, a BICM (Bit interleaved coding &modulation) block 1010, a frame structure block 1020, an OFDM(Orthogonal Frequency Division Multiplexing) generation block 1030 and asignaling generation block 1040. A description will be given of theoperation of each module of the apparatus for transmitting broadcastsignals.

IP stream/packets and MPEG2-TS are the main input formats, other streamtypes are handled as General Streams. In addition to these data inputs,Management Information is input to control the scheduling and allocationof the corresponding bandwidth for each input stream. One or multiple TSstream(s), IP stream(s) and/or General Stream(s) inputs aresimultaneously allowed.

The input formatting block 1000 can demultiplex each input stream intoone or multiple data pipe(s), to each of which an independent coding andmodulation is applied. The data pipe (DP) is the basic unit forrobustness control, thereby affecting quality-of-service (QoS). One ormultiple service(s) or service component(s) can be carried by a singleDP. Details of operations of the input formatting block 1000 will bedescribed later.

The data pipe is a logical channel in the physical layer that carriesservice data or related metadata, which may carry one or multipleservice(s) or service component(s).

Also, the data pipe unit: a basic unit for allocating data cells to a DPin a frame.

In the BICM block 1010, parity data is added for error correction andthe encoded bit streams are mapped to complex-value constellationsymbols. The symbols are interleaved across a specific interleavingdepth that is used for the corresponding DP. For the advanced profile,MIMO encoding is performed in the BICM block 1010 and the additionaldata path is added at the output for MIMO transmission. Details ofoperations of the BICM block 1010 will be described later.

The Frame Building block 1020 can map the data cells of the input DPsinto the OFDM symbols within a frame. After mapping, the frequencyinterleaving is used for frequency-domain diversity, especially tocombat frequency-selective fading channels. Details of operations of theFrame Building block 1020 will be described later.

After inserting a preamble at the beginning of each frame, the OFDMGeneration block 1030 can apply conventional OFDM modulation having acyclic prefix as guard interval. For antenna space diversity, adistributed MISO scheme is applied across the transmitters. In addition,a Peak-to-Average Power Reduction (PAPR) scheme is performed in the timedomain. For flexible network planning, this proposal provides a set ofvarious FFT sizes, guard interval lengths and corresponding pilotpatterns. Details of operations of the OFDM Generation block 1030 willbe described later.

The Signaling Generation block 1040 can create physical layer signalinginformation used for the operation of each functional block. Thissignaling information is also transmitted so that the services ofinterest are properly recovered at the receiver side. Details ofoperations of the Signaling Generation block 1040 will be describedlater.

FIGS. 2, 3 and 4 illustrate the input formatting block 1000 according toembodiments of the present invention. A description will be given ofeach figure.

FIG. 2 illustrates an input formatting block according to one embodimentof the present invention. FIG. 2 shows an input formatting module whenthe input signal is a single input stream.

The input formatting block illustrated in FIG. 2 corresponds to anembodiment of the input formatting block 1000 described with referenceto FIG. 1.

The input to the physical layer may be composed of one or multiple datastreams. Each data stream is carried by one DP. The mode adaptationmodules slice the incoming data stream into data fields of the basebandframe (BBF). The system supports three types of input data streams:MPEG2-TS, Internet protocol (IP) and Generic stream (GS). MPEG2-TS ischaracterized by fixed length (188 byte) packets with the first bytebeing a sync-byte (0x47).

An IP stream is composed of variable length IP datagram packets, assignaled within IP packet headers. The system supports both IPv4 andIPv6 for the IP stream. GS may be composed of variable length packets orconstant length packets, signaled within encapsulation packet headers.

(a) shows a mode adaptation block 2000 and a stream adaptation 2010 forsignal DP and (b) shows a PLS generation block 2020 and a PLS scrambler2030 for generating and processing PLS data. A description will be givenof the operation of each block.

The Input Stream Splitter splits the input TS, IP, GS streams intomultiple service or service component (audio, video, etc.) streams. Themode adaptation module 2010 is comprised of a CRC Encoder, BB (baseband)Frame Slicer, and BB Frame Header Insertion block.

The CRC Encoder provides three kinds of CRC encoding for error detectionat the user packet (UP) level, i.e., CRC-8, CRC-16, and CRC-32. Thecomputed CRC bytes are appended after the UP. CRC-8 is used for TS stream and CRC-32 for IP stream. If the GS stream doesn't provide the CRCencoding, the proposed CRC encoding should be applied.

BB Frame Slicer maps the input into an internal logical-bit format. Thefirst received bit is defined to be the MSB. The BB Frame Slicerallocates a number of input bits equal to the available data fieldcapacity. To allocate a number of input bits equal to the BBF payload,the UP packet stream is sliced to fit the data field of BBF.

BB Frame Header Insertion block can insert fixed length BBF header of 2bytes is inserted in front of the BB Frame. The BBF header is composedof STUFFI (1 bit), SYNCD (13 bits), and RFU (2 bits). In addition to thefixed 2-Byte BBF header, BBF can have an extension field (1 or 3 bytes)at the end of the 2-byte BBF header.

The stream adaptation 2010 is comprised of stuffing insertion block andBB scrambler.

The stuffing insertion block can insert stuffing field into a payload ofa BB frame. If the input data to the stream adaptation is sufficient tofill a BB-Frame, STUFFI is set to ‘0’ and the BBF has no stuffing field.Otherwise STUFFI is set to ‘1’ and the stuffing field is insertedimmediately after the BBF header. The stuffing field comprises two bytesof the stuffing field header and a variable size of stuffing data.

The BB scrambler scrambles complete BBF for energy dispersal. Thescrambling sequence is synchronous with the BBF. The scrambling sequenceis generated by the feed-back shift register.

The PLS generation block 2020 can generate physical layer signaling(PLS) data. The PLS provides the receiver with a means to accessphysical layer DPs. The PLS data consists of PLS1 data and PLS2 data.

The PLS1 data is a first set of PLS data carried in the FSS symbols inthe frame having a fixed size, coding and modulation, which carriesbasic information about the system as well as the parameters needed todecode the PLS2 data. The PLS1 data provides basic transmissionparameters including parameters required to enable the reception anddecoding of the PLS2 data. Also, the PLS1 data remains constant for theduration of a frame-group.

The PLS2 data is a second set of PLS data transmitted in the FSS symbol,which carries more detailed PLS data about the system and the DPs. ThePLS2 contains parameters that provide sufficient information for thereceiver to decode the desired DP. The PLS2 signaling further consistsof two types of parameters, PLS2 Static data (PLS2-STAT data) and PLS2dynamic data (PLS2-DYN data). The PLS2 Static data is PLS2 data thatremains static for the duration of a frame-group and the PLS2 dynamicdata is PLS2 data that may dynamically change frame-by-frame.

Details of the PLS data will be described later.

The PLS scrambler 2030 can scramble the generated PLS data for energydispersal.

The above-described blocks may be omitted or replaced by blocks havingsimilar or identical functions.

FIG. 3 illustrates an input formatting block according to anotherembodiment of the present invention.

The input formatting block illustrated in FIG. 3 corresponds to anembodiment of the input formatting block 1000 described with referenceto FIG. 1.

FIG. 3 shows a mode adaptation block of the input formatting block whenthe input signal corresponds to multiple input streams.

The mode adaptation block of the input formatting block for processingthe multiple input streams can independently process the multiple inputstreams.

Referring to FIG. 3, the mode adaptation block for respectivelyprocessing the multiple input streams can include an input streamsplitter 3000, an input stream synchronizer 3010, a compensating delayblock 3020, a null packet deletion block 3030, a head compression block3040, a CRC encoder 3050, a BB frame slicer 3060 and a BB headerinsertion block 3070. Description will be given of each block of themode adaptation block.

Operations of the CRC encoder 3050, BB frame slicer 3060 and BB headerinsertion block 3070 correspond to those of the CRC encoder, BB frameslicer and BB header insertion block described with reference to FIG. 2and thus description thereof is omitted.

The input stream splitter 3000 can split the input TS, IP, GS streamsinto multiple service or service component (audio, video, etc.) streams.

The input stream synchronizer 3010 may be referred as ISSY. The ISSY canprovide suitable means to guarantee Constant Bit Rate (CBR) and constantend-to-end transmission delay for any input data format. The ISSY isalways used for the case of multiple DPs carrying TS, and optionallyused for multiple DPs carrying GS streams.

The compensating delay block 3020 can delay the split TS packet streamfollowing the insertion of ISSY information to allow a TS packetrecombining mechanism without requiring additional memory in thereceiver.

The null packet deletion block 3030, is used only for the TS inputstream case. Some TS input streams or split TS streams may have a largenumber of null-packets present in order to accommodate VBR (variablebit-rate) services in a CBR TS stream. In this case, in order to avoidunnecessary transmission overhead, null-packets can be identified andnot transmitted. In the receiver, removed null-packets can bere-inserted in the exact place where they were originally by referenceto a deleted null-packet (DNP) counter that is inserted in thetransmission, thus guaranteeing constant bit-rate and avoiding the needfor time-stamp (PCR) updating.

The head compression block 3040 can provide packet header compression toincrease transmission efficiency for TS or IP input streams. Because thereceiver can have a priori information on certain parts of the header,this known information can be deleted in the transmitter.

For Transport Stream, the receiver has a-priori information about thesync-byte configuration (0x47) and the packet length (188 Byte). If theinput TS stream carries content that has only one PID, i.e., for onlyone service component (video, audio, etc.) or service sub-component (SVCbase layer, SVC enhancement layer, MVC base view or MVC dependentviews), TS packet header compression can be applied (optionally) to theTransport Stream. IP packet header compression is used optionally if theinput steam is an IP stream.

The above-described blocks may be omitted or replaced by blocks havingsimilar or identical functions.

FIG. 4 illustrates an input formatting block according to anotherembodiment of the present invention.

The input formatting block illustrated in FIG. 4 corresponds to anembodiment of the input formatting block 1000 described with referenceto FIG. 1.

FIG. 4 illustrates a stream adaptation block of the input formattingmodule when the input signal corresponds to multiple input streams.

Referring to FIG. 4, the mode adaptation block for respectivelyprocessing the multiple input streams can include a scheduler 4000, an1-Frame delay block 4010, a stuffing insertion block 4020, an in-bandsignaling 4030, a BB Frame scrambler 4040, a PLS generation block 4050and a PLS scrambler 4060. Description will be given of each block of thestream adaptation block.

Operations of the stuffing insertion block 4020, the BB Frame scrambler4040, the PLS generation block 4050 and the PLS scrambler 4060correspond to those of the stuffing insertion block, BB scrambler, PLSgeneration block and the PLS scrambler described with reference to FIG.2 and thus description thereof is omitted.

The scheduler 4000 can determine the overall cell allocation across theentire frame from the amount of FECBLOCKs of each DP. Including theallocation for PLS, EAC and FIC, the scheduler generate the values ofPLS2-DYN data, which is transmitted as in-band signaling or PLS cell inFSS of the frame. Details of FECBLOCK, EAC and FIC will be describedlater.

The 1-Frame delay block 4010 can delay the input data by onetransmission frame such that scheduling information about the next framecan be transmitted through the current frame for in-band signalinginformation to be inserted into the DPs.

The in-band signaling 4030 can insert un-delayed part of the PLS2 datainto a DP of a frame.

The above-described blocks may be omitted or replaced by blocks havingsimilar or identical functions.

FIG. 5 illustrates a BICM block according to an embodiment of thepresent invention.

The BICM block illustrated in FIG. 5 corresponds to an embodiment of theBICM block 1010 described with reference to FIG. 1.

As described above, the apparatus for transmitting broadcast signals forfuture broadcast services according to an embodiment of the presentinvention can provide a terrestrial broadcast service, mobile broadcastservice, UHDTV service, etc.

Since QoS (quality of service) depends on characteristics of a serviceprovided by the apparatus for transmitting broadcast signals for futurebroadcast services according to an embodiment of the present invention,data corresponding to respective services needs to be processed throughdifferent schemes. Accordingly, the a BICM block according to anembodiment of the present invention can independently process DPs inputthereto by independently applying SISO, MISO and MIMO schemes to thedata pipes respectively corresponding to data paths. Consequently, theapparatus for transmitting broadcast signals for future broadcastservices according to an embodiment of the present invention can controlQoS for each service or service component transmitted through each DP.

(a) shows the BICM block shared by the base profile and the handheldprofile and (b) shows the BICM block of the advanced profile.

The BICM block shared by the base profile and the handheld profile andthe BICM block of the advanced profile can include plural processingblocks for processing each DP.

A description will be given of each processing block of the BICM blockfor the base profile and the handheld profile and the BICM block for theadvanced profile.

A processing block 5000 of the BICM block for the base profile and thehandheld profile can include a Data FEC encoder 5010, a bit interleaver5020, a constellation mapper 5030, an SSD (Signal Space Diversity)encoding block 5040 and a time interleaver 5050.

The Data FEC encoder 5010 can perform the FEC encoding on the input BBFto generate FECBLOCK procedure using outer coding (BCH), and innercoding (LDPC). The outer coding (BCH) is optional coding method. Detailsof operations of the Data FEC encoder 5010 will be described later.

The bit interleaver 5020 can interleave outputs of the Data FEC encoder5010 to achieve optimized performance with combination of the LDPC codesand modulation scheme while providing an efficiently implementablestructure. Details of operations of the bit interleaver 5020 will bedescribed later.

The constellation mapper 5030 can modulate each cell word from the bitinterleaver 5020 in the base and the handheld profiles, or cell wordfrom the Cell-word demultiplexer 5010−1 in the advanced profile usingeither QPSK, QAM-16, non-uniform QAM (NUQ-64, NUQ-256, NUQ-1024) ornon-uniform constellation (NUC-16, NUC-64, NUC-256, NUC-1024) to give apower-normalized constellation point, e_(l). This constellation mappingis applied only for DPs. Observe that QAM-16 and NUQs are square shaped,while NUCs have arbitrary shape. When each constellation is rotated byany multiple of 90 degrees, the rotated constellation exactly overlapswith its original one. This “rotation-sense” symmetric property makesthe capacities and the average powers of the real and imaginarycomponents equal to each other. Both NUQs and NUCs are definedspecifically for each code rate and the particular one used is signaledby the parameter DP_MOD filed in PLS2 data.

The SSD encoding block 5040 can precode cells in two (2D), three (3D),and four (4D) dimensions to increase the reception robustness underdifficult fading conditions.

The time interleaver 5050 can operates at the DP level. The parametersof time interleaving (TI) may be set differently for each DP. Details ofoperations of the time interleaver 5050 will be described later.

A processing block 5000−1 of the BICM block for the advanced profile caninclude the Data FEC encoder, bit interleaver, constellation mapper, andtime interleaver. However, the processing block 5000−1 is distinguishedfrom the processing block 5000 further includes a cell-worddemultiplexer 5010−1 and a MIMO encoding block 5020−1.

Also, the operations of the Data FEC encoder, bit interleaver,constellation mapper, and time interleaver in the processing block5000−1 correspond to those of the Data FEC encoder 5010, bit interleaver5020, constellation mapper 5030, and time interleaver 5050 described andthus description thereof is omitted.

The cell-word demultiplexer 5010−1 is used for the DP of the advancedprofile to divide the single cell-word stream into dual cell-wordstreams for MIMO processing. Details of operations of the cell-worddemultiplexer 5010−1 will be described later.

The MIMO encoding block 5020−1 can processing the output of thecell-word demultiplexer 5010−1 using MIMO encoding scheme. The MIMOencoding scheme was optimized for broadcasting signal transmission. TheMIMO technology is a promising way to get a capacity increase but itdepends on channel characteristics. Especially for broadcasting, thestrong LOS component of the channel or a difference in the receivedsignal power between two antennas caused by different signal propagationcharacteristics makes it difficult to get capacity gain from MIMO. Theproposed MIMO encoding scheme overcomes this problem using arotation-based pre-coding and phase randomization of one of the MIMOoutput signals.

MIMO encoding is intended for a 2×2 MIMO system requiring at least twoantennas at both the transmitter and the receiver. Two MIMO encodingmodes are defined in this proposal; full-rate spatial multiplexing(FR-SM) and full-rate full-diversity spatial multiplexing (FRFD-SM). TheFR-SM encoding provides capacity increase with relatively smallcomplexity increase at the receiver side while the FRFD-SM encodingprovides capacity increase and additional diversity gain with a greatcomplexity increase at the receiver side. The proposed MIMO encodingscheme has no restriction on the antenna polarity configuration.

MIMO processing is required for the advanced profile frame, which meansall DPs in the advanced profile frame are processed by the MIMO encoder.MIMO processing is applied at DP level. Pairs of the ConstellationMapper outputs NUQ (e_(1,i), and e_(2,i)) are fed to the input of theMIMO Encoder. Paired MIMO Encoder output (g1,i and g2,i) is transmittedby the same carrier k and OFDM symbol 1 of their respective TX antennas.

The above-described blocks may be omitted or replaced by blocks havingsimilar or identical functions.

FIG. 6 illustrates a BICM block according to another embodiment of thepresent invention.

The BICM block illustrated in FIG. 6 corresponds to an embodiment of theBICM block 1010 described with reference to FIG. 1.

FIG. 6 illustrates a BICM block for protection of physical layersignaling (PLS), emergency alert channel (EAC) and fast informationchannel (FIC). EAC is a part of a frame that carries EAS informationdata and FIC is a logical channel in a frame that carries the mappinginformation between a service and the corresponding base DP. Details ofthe EAC and FIC will be described later.

Referring to FIG. 6, the BICM block for protection of PLS, EAC and FICcan include a PLS FEC encoder 6000, a bit interleaver 6010, aconstellation mapper 6020 and time interleaver 6030.

Also, the PLS FEC encoder 6000 can include a scrambler, BCHencoding/zero insertion block, LDPC encoding block and LDPC paritypunturing block. Description will be given of each block of the BICMblock.

The PLS FEC encoder 6000 can encode the scrambled PLS 1/2 data, EAC andFIC section.

The scrambler can scramble PLS1 data and PLS2 data before BCH encodingand shortened and punctured LDPC encoding.

The BCH encoding/zero insertion block can perform outer encoding on thescrambled PLS 1/2 data using the shortened BCH code for PLS protectionand insert zero bits after the BCH encoding. For PLS1 data only, theoutput bits of the zero insertion may be permutted before LDPC encoding.

The LDPC encoding block can encode the output of the BCH encoding/zeroinsertion block using LDPC code. To generate a complete coded block,C_(ldpc), parity bits, P_(ldpc) are encoded systematically from eachzero-inserted PLS information block, I_(ldpc) and appended after it.C _(ldpc) =[I _(ldpc) P _(ldpc) ]=[i ₀ , i ₁ , . . . , i _(K) _(ldpc) ⁻¹, p ₀ , p ₁ , . . . , p _(N) _(ldpc) _(−K) _(ldpc) ⁻¹]  [Expression 1]

The LDPC code parameters for PLS1 and PLS2 are as following table 4.

TABLE 4 Signaling K_(ldpc) code Type K_(sig) K_(bch) N_(bch)_parity(=N_(bch)) N_(ldpc) N_(ldpc)_parity rate Q_(ldpc) PLS1 342 1020 60 10804320 3240 1/4  36 PLS2 <1021 >1020 2100 2160 7200 5040 3/10 56

The LDPC parity punturing block can perform puncturing on the PLS1 dataand PLS2 data.

When shortening is applied to the PLS1 data protection, some LDPC paritybits are punctured after LDPC encoding. Also, for the PLS2 dataprotection, the LDPC parity bits of PLS2 are punctured after LDPCencoding. These punctured bits are not transmitted.

The bit interleaver 6010 can interleave the each shortened and puncturedPLS1 data and PLS2 data.

The constellation mapper 6020 can map the bit ineterlaeved PLS1 data andPLS2 data onto constellations.

The time interleaver 6030 can interleave the mapped PLS1 data and PLS2data.

The above-described blocks may be omitted or replaced by blocks havingsimilar or identical functions.

FIG. 7 illustrates a frame building block according to one embodiment ofthe present invention.

The frame building block illustrated in FIG. 7 corresponds to anembodiment of the frame building block 1020 described with reference toFIG. 1.

Referring to FIG. 7, the frame building block can include a delaycompensation block 7000, a cell mapper 7010 and a frequency interleaver7020. Description will be given of each block of the frame buildingblock.

The delay compensation block 7000 can adjust the timing between the datapipes and the corresponding PLS data to ensure that they are co-timed atthe transmitter end. The PLS data is delayed by the same amount as datapipes are by addressing the delays of data pipes caused by the InputFormatting block and BICM block. The delay of the BICM block is mainlydue to the time interleaver. In-band signaling data carries informationof the next TI group so that they are carried one frame ahead of the DPsto be signaled. The Delay Compensating block delays in-band signalingdata accordingly.

The cell mapper 7010 can map PLS, EAC, FIC, DPs, auxiliary streams anddummy cells into the active carriers of the OFDM symbols in the frame.The basic function of the cell mapper 7010 is to map data cells producedby the TIs for each of the DPs, PLS cells, and EAC/FIC cells, if any,into arrays of active OFDM cells corresponding to each of the OFDMsymbols within a frame. Service signaling data (such as PSI (programspecific information)/SI) can be separately gathered and sent by a datapipe. The Cell Mapper operates according to the dynamic informationproduced by the scheduler and the configuration of the frame structure.Details of the frame will be described later.

The frequency interleaver 7020 can randomly interleave data cellsreceived from the cell mapper 7010 to provide frequency diversity. Also,the frequency interleaver 7020 can operate on very OFDM symbol paircomprised of two sequential OFDM symbols using a differentinterleaving-seed order to get maximum interleaving gain in a singleframe.

The above-described blocks may be omitted or replaced by blocks havingsimilar or identical functions.

FIG. 8 illustrates an OFMD generation block according to an embodimentof the present invention.

The OFMD generation block illustrated in FIG. 8 corresponds to anembodiment of the OFMD generation block 1030 described with reference toFIG. 1.

The OFDM generation block modulates the OFDM carriers by the cellsproduced by the Frame Building block, inserts the pilots, and producesthe time domain signal for transmission. Also, this block subsequentlyinserts guard intervals, and applies PAPR (Peak-to-Average Power Radio)reduction processing to produce the final RF signal.

Referring to FIG. 8, the frame building block can include a pilot andreserved tone insertion block 8000, a 2D-eSFN encoding block 8010, anIFFT (Inverse Fast Fourier Transform) block 8020, a PAPR reduction block8030, a guard interval insertion block 8040, a preamble insertion block8050, other system insertion block 8060 and a DAC block 8070.Description will be given of each block of the frame building block.

The pilot and reserved tone insertion block 8000 can insert pilots andthe reserved tone.

Various cells within the OFDM symbol are modulated with referenceinformation, known as pilots, which have transmitted values known apriori in the receiver. The information of pilot cells is made up ofscattered pilots, continual pilots, edge pilots, FSS (frame signalingsymbol) pilots and FES (frame edge symbol) pilots. Each pilot istransmitted at a particular boosted power level according to pilot typeand pilot pattern. The value of the pilot information is derived from areference sequence, which is a series of values, one for eachtransmitted carrier on any given symbol. The pilots can be used forframe synchronization, frequency synchronization, time synchronization,channel estimation, and transmission mode identification, and also canbe used to follow the phase noise.

Reference information, taken from the reference sequence, is transmittedin scattered pilot cells in every symbol except the preamble, FSS andFES of the frame. Continual pilots are inserted in every symbol of theframe. The number and location of continual pilots depends on both theFFT size and the scattered pilot pattern. The edge carriers are edgepilots in every symbol except for the preamble symbol. They are insertedin order to allow frequency interpolation up to the edge of thespectrum. FSS pilots are inserted in FSS(s) and FES pilots are insertedin FES. They are inserted in order to allow time interpolation up to theedge of the frame.

The system according to an embodiment of the present invention supportsthe SFN network, where distributed MISO scheme is optionally used tosupport very robust transmission mode. The 2D-eSFN is a distributed MISOscheme that uses multiple TX antennas, each of which is located in thedifferent transmitter site in the SFN network.

The 2D-eSFN encoding block 8010 can process a 2D-eSFN processing todistorts the phase of the signals transmitted from multipletransmitters, in order to create both time and frequency diversity inthe SFN configuration. Hence, burst errors due to low flat fading ordeep-fading for a long time can be mitigated.

The IFFT block 8020 can modulate the output from the 2D-eSFN encodingblock 8010 using OFDM modulation scheme. Any cell in the data symbolswhich has not been designated as a pilot (or as a reserved tone) carriesone of the data cells from the frequency interleaver. The cells aremapped to OFDM carriers.

The PAPR reduction block 8030 can perform a PAPR reduction on inputsignal using various PAPR reduction algorithm in the time domain.

The guard interval insertion block 8040 can insert guard intervals andthe preamble insertion block 8050 can insert preamble in front of thesignal. Details of a structure of the preamble will be described later.The other system insertion block 8060 can multiplex signals of aplurality of broadcast transmission/reception systems in the time domainsuch that data of two or more different broadcast transmission/receptionsystems providing broadcast services can be simultaneously transmittedin the same RF signal bandwidth. In this case, the two or more differentbroadcast transmission/reception systems refer to systems providingdifferent broadcast services. The different broadcast services may referto a terrestrial broadcast service, mobile broadcast service, etc. Datarelated to respective broadcast services can be transmitted throughdifferent frames.

The DAC block 8070 can convert an input digital signal into an analogsignal and output the analog signal. The signal output from the DACblock 7800 can be transmitted through multiple output antennas accordingto the physical layer profiles. A Tx antenna according to an embodimentof the present invention can have vertical or horizontal polarity.

The above-described blocks may be omitted or replaced by blocks havingsimilar or identical functions according to design.

FIG. 9 illustrates a structure of an apparatus for receiving broadcastsignals for future broadcast services according to an embodiment of thepresent invention.

The apparatus for receiving broadcast signals for future broadcastservices according to an embodiment of the present invention cancorrespond to the apparatus for transmitting broadcast signals forfuture broadcast services, described with reference to FIG. 1.

The apparatus for receiving broadcast signals for future broadcastservices according to an embodiment of the present invention can includea synchronization & demodulation module 9000, a frame parsing module9010, a demapping & decoding module 9020, an output processor 9030 and asignaling decoding module 9040. A description will be given of operationof each module of the apparatus for receiving broadcast signals.

The synchronization & demodulation module 9000 can receive input signalsthrough m Rx antennas, perform signal detection and synchronization withrespect to a system corresponding to the apparatus for receivingbroadcast signals and carry out demodulation corresponding to a reverseprocedure of the procedure performed by the apparatus for transmittingbroadcast signals.

The frame parsing module 9100 can parse input signal frames and extractdata through which a service selected by a user is transmitted. If theapparatus for transmitting broadcast signals performs interleaving, theframe parsing module 9100 can carry out deinterleaving corresponding toa reverse procedure of interleaving. In this case, the positions of asignal and data that need to be extracted can be obtained by decodingdata output from the signaling decoding module 9400 to restorescheduling information generated by the apparatus for transmittingbroadcast signals.

The demapping & decoding module 9200 can convert the input signals intobit domain data and then deinterleave the same as necessary. Thedemapping & decoding module 9200 can perform demapping for mappingapplied for transmission efficiency and correct an error generated on atransmission channel through decoding. In this case, the demapping &decoding module 9200 can obtain transmission parameters necessary fordemapping and decoding by decoding the data output from the signalingdecoding module 9400.

The output processor 9300 can perform reverse procedures of variouscompression/signal processing procedures which are applied by theapparatus for transmitting broadcast signals to improve transmissionefficiency. In this case, the output processor 9300 can acquirenecessary control information from data output from the signalingdecoding module 9400. The output of the output processor 8300corresponds to a signal input to the apparatus for transmittingbroadcast signals and may be MPEG-TSs, IP streams (v4 or v6) and genericstreams.

The signaling decoding module 9400 can obtain PLS information from thesignal demodulated by the synchronization & demodulation module 9000. Asdescribed above, the frame parsing module 9100, demapping & decodingmodule 9200 and output processor 9300 can execute functions thereofusing the data output from the signaling decoding module 9400.

FIG. 10 illustrates a frame structure according to an embodiment of thepresent invention.

FIG. 10 shows an example configuration of the frame types and FRUs in asuper-frame. (a) shows a super frame according to an embodiment of thepresent invention, (b) shows FRU (Frame Repetition Unit) according to anembodiment of the present invention, (c) shows frames of variable PHYprofiles in the FRU and (d) shows a structure of a frame.

A super-frame may be composed of eight FRUs. The FRU is a basicmultiplexing unit for TDM of the frames, and is repeated eight times ina super-frame.

Each frame in the FRU belongs to one of the PHY profiles, (base,handheld, advanced) or FEF. The maximum allowed number of the frames inthe FRU is four and a given PHY profile can appear any number of timesfrom zero times to four times in the FRU (e.g., base, base, handheld,advanced). PHY profile definitions can be extended using reserved valuesof the PHY_PROFILE in the preamble, if required.

The FEF part is inserted at the end of the FRU, if included. When theFEF is included in the FRU, the minimum number of FEFs is 8 in asuper-frame. It is not recommended that FEF parts be adjacent to eachother.

One frame is further divided into a number of OFDM symbols and apreamble. As shown in (d), the frame comprises a preamble, one or moreframe signaling symbols (FSS), normal data symbols and a frame edgesymbol (FES).

The preamble is a special symbol that enables fast Futurecast UTB systemsignal detection and provides a set of basic transmission parameters forefficient transmission and reception of the signal. The detaileddescription of the preamble will be will be described later.

The main purpose of the FSS(s) is to carry the PLS data. For fastsynchronization and channel estimation, and hence fast decoding of PLSdata, the FSS has more dense pilot pattern than the normal data symbol.The FES has exactly the same pilots as the FSS, which enablesfrequency-only interpolation within the FES and temporal interpolation,without extrapolation, for symbols immediately preceding the FES.

FIG. 11 illustrates a signaling hierarchy structure of the frameaccording to an embodiment of the present invention.

FIG. 11 illustrates the signaling hierarchy structure, which is splitinto three main parts: the preamble signaling data 11000, the PLS1 data11010 and the PLS2 data 11020. The purpose of the preamble, which iscarried by the preamble symbol in every frame, is to indicate thetransmission type and basic transmission parameters of that frame. ThePLS1 enables the receiver to access and decode the PLS2 data, whichcontains the parameters to access the DP of interest. The PLS2 iscarried in every frame and split into two main parts: PLS2-STAT data andPLS2-DYN data. The static and dynamic portion of PLS2 data is followedby padding, if necessary.

FIG. 12 illustrates preamble signaling data according to an embodimentof the present invention.

Preamble signaling data carries 21 bits of information that are neededto enable the receiver to access PLS data and trace DPs within the framestructure. Details of the preamble signaling data are as follows:

PHY_PROFILE: This 3-bit field indicates the PHY profile type of thecurrent frame. The mapping of different PHY profile types is given inbelow table 5.

TABLE 5 Value PHY profile 000 Base profile 001 Handheld profile 010Advanced profiled 011~110 Reserved 111 FEF

FFT_SIZE: This 2 bit field indicates the FFT size of the current framewithin a frame-group, as described in below table 6.

TABLE 6 Value FFT size 00  8K FFT 01 16K FFT 10 32K FFT 11 Reserved

GI_FRACTION: This 3 bit field indicates the guard interval fractionvalue in the current super-frame, as described in below table 7.

TABLE 7 Value GI_FRACTION 000 1/5 001 1/10 010 1/20 011 1/40 100 1/80101 1/160 110~111 Reserved

EAC_FLAG: This 1 bit field indicates whether the EAC is provided in thecurrent frame. If this field is set to ‘1’, emergency alert service(EAS) is provided in the current frame. If this field set to ‘0’, EAS isnot carried in the current frame. This field can be switched dynamicallywithin a super-frame.

PILOT_MODE: This 1-bit field indicates whether the pilot mode is mobilemode or fixed mode for the current frame in the current frame-group. Ifthis field is set to ‘0’, mobile pilot mode is used. If the field is setto ‘1’, the fixed pilot mode is used.

PAPR_FLAG: This 1-bit field indicates whether PAPR reduction is used forthe current frame in the current frame-group. If this field is set tovalue ‘1’, tone reservation is used for PAPR reduction. If this field isset to ‘0’, PAPR reduction is not used.

FRU_CONFIGURE: This 3-bit field indicates the PHY profile typeconfigurations of the frame repetition units (FRU) that are present inthe current super-frame. All profile types conveyed in the currentsuper-frame are identified in this field in all preambles in the currentsuper-frame. The 3-bit field has a different definition for eachprofile, as show in below table 8.

TABLE 8 Current Current Current PHY_PROFILE = PHY_PROFILE = CurrentPHY_PROFILE = ‘001’ ‘010’ PHY_PROFILE = ‘000’ (base) (handheld)(advanced) ‘111’ (FEF) FRU_CONFIGURE = Only base Only handheld Onlyadvanced Only FEF 000 profile present profile present profile presentpresent FRU_CONFIGURE = Handheld profile Base profile Base profile Baseprofile 1XX present present present present FRU_CONFIGURE = AdvancedAdvanced Handheld profile Handheld profile X1X profile present profilepresent present present FRU_CONFIGURE = FEF present FEF present FEFpresent Advanced XX1 profile present

RESERVED: This 7-bit field is reserved for future use.

FIG. 13 illustrates PLS1 data according to an embodiment of the presentinvention.

PLS1 data provides basic transmission parameters including parametersrequired to enable the reception and decoding of the PLS2. As abovementioned, the PLS1 data remain unchanged for the entire duration of oneframe-group. The detailed definition of the signaling fields of the PLS1data are as follows:

PREAMBLE_DATA: This 20-bit field is a copy of the preamble signalingdata excluding the EAC_FLAG.

NUM_FRAME_FRU: This 2-bit field indicates the number of the frames perFRU.

PAYLOAD_TYPE: This 3-bit field indicates the format of the payload datacarried in the frame-group. PAYLOAD_TYPE is signaled as shown in table9.

TABLE 9 value Payload type 1XX TS stream is transmitted X1X IP stream istransmitted XX1 GS stream is transmitted

NUM_FSS: This 2-bit field indicates the number of FSS symbols in thecurrent frame.

SYSTEM_VERSION: This 8-bit field indicates the version of thetransmitted signal format. The SYSTEM_VERSION is divided into two 4-bitfields, which are a major version and a minor version.

Major version: The MSB four bits of SYSTEM_VERSION field indicate majorversion information. A change in the major version field indicates anon-backward-compatible change. The default value is ‘0000’. For theversion described in this standard, the value is set to ‘0000’.

Minor version: The LSB four bits of SYSTEM_VERSION field indicate minorversion information. A change in the minor version field isbackward-compatible.

CELL_ID: This is a 16-bit field which uniquely identifies a geographiccell in an ATSC network. An ATSC cell coverage area may consist of oneor more frequencies, depending on the number of frequencies used perFuturecast UTB system. If the value of the CELL_ID is not known orunspecified, this field is set to ‘0’.

NETWORK_ID: This is a 16-bit field which uniquely identifies the currentATSC network.

SYSTEM_ID: This 16-bit field uniquely identifies the Futurecast UTBsystem within the ATSC network. The Futurecast UTB system is theterrestrial broadcast system whose input is one or more input streams(TS, IP, GS) and whose output is an RF signal. The Futurecast UTB systemcarries one or more PHY profiles and FEF, if any. The same FuturecastUTB system may carry different input streams and use different RFfrequencies in different geographical areas, allowing local serviceinsertion. The frame structure and scheduling is controlled in one placeand is identical for all transmissions within a Futurecast UTB system.One or more Futurecast UTB systems may have the same SYSTEM_ID meaningthat they all have the same physical layer structure and configuration.

The following loop consists of FRU_PHY_PROFILE, FRU_FRAME_LENGTH,FRU_GI_FRACTION, and RESERVED which are used to indicate the FRUconfiguration and the length of each frame type. The loop size is fixedso that four PHY profiles (including a FEF) are signaled within the FRU.If NUM_FRAME_FRU is less than 4, the unused fields are filled withzeros.

FRU_PHY_PROFILE: This 3-bit field indicates the PHY profile type of the(i+1)^(th) (i is the loop index) frame of the associated FRU. This fielduses the same signaling format as shown in the table 8.

FRU_FRAME_LENGTH: This 2-bit field indicates the length of the(i+1)^(th) frame of the associated FRU. Using FRU_FRAME_LENGTH togetherwith FRU_GI_FRACTION, the exact value of the frame duration can beobtained.

FRU_GI_FRACTION: This 3-bit field indicates the guard interval fractionvalue of the (i+1)^(th) frame of the associated FRU. FRU_GI_FRACTION issignaled according to the table 7.

RESERVED: This 4-bit field is reserved for future use.

The following fields provide parameters for decoding the PLS2 data.

PLS2_FEC_TYPE: This 2-bit field indicates the FEC type used by the PLS2protection. The FEC type is signaled according to table 10. The detailsof the LDPC codes will be described later.

TABLE 10 Content PLS2 FEC type 00 4K-1/4 and 7K-3/10 LDPC codes 01~11Reserved

PLS2_MOD: This 3-bit field indicates the modulation type used by thePLS2. The modulation type is signaled according to table 11.

TABLE 11 Value PLS2_MODE 000 BPSK 001 QPSK 010 QAM-16 011 NUQ-64 100~111Reserved

PLS2_SIZE_CELL: This 15-bit field indicates C_(total) _(_) _(partial)_(_) _(block), the size (specified as the number of QAM cells) of thecollection of full coded blocks for PLS2 that is carried in the currentframe-group. This value is constant during the entire duration of thecurrent frame-group.

PLS2_STAT_SIZE_BIT: This 14-bit field indicates the size, in bits, ofthe PLS2-STAT for the current frame-group. This value is constant duringthe entire duration of the current frame-group.

PLS2_DYN_SIZE_BIT: This 14-bit field indicates the size, in bits, of thePLS2-DYN for the current frame-group. This value is constant during theentire duration of the current frame-group.

PLS2_REP_FLAG: This 1-bit flag indicates whether the PLS2 repetitionmode is used in the current frame-group. When this field is set to value‘1’, the PLS2 repetition mode is activated. When this field is set tovalue ‘0’, the PLS2 repetition mode is deactivated.

PLS2_REP_SIZE_CELL: This 15-bit field indicates C_(total) _(_)_(partial) _(_) _(block), the size (specified as the number of QAMcells) of the collection of partial coded blocks for PLS2 carried inevery frame of the current frame-group, when PLS2 repetition is used. Ifrepetition is not used, the value of this field is equal to 0. Thisvalue is constant during the entire duration of the current frame-group.

PLS2_NEXT_FEC_TYPE: This 2-bit field indicates the FEC type used forPLS2 that is carried in every frame of the next frame-group. The FECtype is signaled according to the table 10.

PLS2_NEXT_MOD: This 3-bit field indicates the modulation type used forPLS2 that is carried in every frame of the next frame-group. Themodulation type is signaled according to the table 11.

PLS2_NEXT_REP_FLAG: This 1-bit flag indicates whether the PLS2repetition mode is used in the next frame-group. When this field is setto value ‘1’, the PLS2 repetition mode is activated. When this field isset to value ‘0’, the PLS2 repetition mode is deactivated.

PLS2_NEXT_REP_SIZE_CELL: This 15-bit field indicates C_(total) _(_)_(full) _(_) _(block), The size (specified as the number of QAM cells)of the collection of full coded blocks for PLS2 that is carried in everyframe of the next frame-group, when PLS2 repetition is used. Ifrepetition is not used in the next frame-group, the value of this fieldis equal to 0. This value is constant during the entire duration of thecurrent frame-group.

PLS2_NEXT_REP_STAT_SIZE_BIT: This 14-bit field indicates the size, inbits, of the PLS2-STAT for the next frame-group. This value is constantin the current frame-group.

PLS2_NEXT_REP_DYN_SIZE_BIT: This 14-bit field indicates the size, inbits, of the PLS2-DYN for the next frame-group. This value is constantin the current frame-group.

PLS2_AP_MODE: This 2-bit field indicates whether additional parity isprovided for PLS2 in the current frame-group. This value is constantduring the entire duration of the current frame-group. The below table12 gives the values of this field. When this field is set to ‘00’,additional parity is not used for the PLS2 in the current frame-group.

TABLE 12 Value PLS2-AP mode 00 AP is not provided 01 AP1 mode 10~11Reserved

PLS2_AP_SIZE_CELL: This 15-bit field indicates the size (specified asthe number of QAM cells) of the additional parity bits of the PLS2. Thisvalue is constant during the entire duration of the current frame-group.

PLS2_NEXT_AP_MODE: This 2-bit field indicates whether additional parityis provided for PLS2 signaling in every frame of next frame-group. Thisvalue is constant during the entire duration of the current frame-group.The table 12 defines the values of this field.

PLS2_NEXT_AP_SIZE_CELL: This 15-bit field indicates the size (specifiedas the number of QAM cells) of the additional parity bits of the PLS2 inevery frame of the next frame-group. This value is constant during theentire duration of the current frame-group.

RESERVED: This 32-bit field is reserved for future use.

CRC_32: A 32-bit error detection code, which is applied to the entirePLS1 signaling.

FIG. 14 illustrates PLS2 data according to an embodiment of the presentinvention.

FIG. 14 illustrates PLS2-STAT data of the PLS2 data. The PLS2-STAT dataare the same within a frame-group, while the PLS2-DYN data provideinformation that is specific for the current frame.

The details of fields of the PLS2-STAT data are as follows:

FIC_FLAG: This 1-bit field indicates whether the FIC is used in thecurrent frame-group. If this field is set to ‘ 1’, the FIC is providedin the current frame. If this field set to ‘0’, the FIC is not carriedin the current frame. This value is constant during the entire durationof the current frame-group.

AUX_FLAG: This 1-bit field indicates whether the auxiliary stream(s) isused in the current frame-group. If this field is set to ‘ 1’, theauxiliary stream is provided in the current frame. If this field set to‘0’, the auxiliary stream is not carried in the current frame. Thisvalue is constant during the entire duration of current frame-group.

NUM_DP: This 6-bit field indicates the number of DPs carried within thecurrent frame. The value of this field ranges from 1 to 64, and thenumber of DPs is NUM_DP+1.

DP_ID: This 6-bit field identifies uniquely a DP within a PHY profile.

DP_TYPE: This 3-bit field indicates the type of the DP. This is signaledaccording to the below table 13.

TABLE 13 Value DP Type 000 DP Type 1 001 DP Type 2 010~111 reserved

DP_GROUP_ID: This 8-bit field identifies the DP group with which thecurrent DP is associated. This can be used by a receiver to access theDPs of the service components associated with a particular service,which will have the same DP_GROUP_ID.

BASE_DP_ID: This 6-bit field indicates the DP carrying service signalingdata (such as PSI/SI) used in the Management layer. The DP indicated byBASE_DP_ID may be either a normal DP carrying the service signaling dataalong with the service data or a dedicated DP carrying only the servicesignaling data

DP_FEC_TYPE: This 2-bit field indicates the FEC type used by theassociated DP. The FEC type is signaled according to the below table 14.

TABLE 14 Value FEC_TYPE 00 16K LDPC 01 64K LDPC 10~11 Reserved

DP_COD: This 4-bit field indicates the code rate used by the associatedDP. The code rate is signaled according to the below table 15.

TABLE 15 Value Code rate 0000 5/15 0001 6/15 0010 7/15 0011 8/15 01009/15 0101 10/15 0110 11/15 0111 12/15 1000 13/15 1001~1111 Reserved

DP_MOD: This 4-bit field indicates the modulation used by the associatedDP. The modulation is signaled according to the below table 16.

TABLE 16 Value Modulation 0000 QPSK 0001 QAM-16 0010 NUQ-64 0011 NUQ-2560100 NUQ-1024 0101 NUC-16 0110 NUC-64 0111 NUC-256 1000 NUC-10241001~1111 reserved

DP_SSD_FLAG: This 1-bit field indicates whether the SSD mode is used inthe associated DP. If this field is set to value ‘1’, SSD is used. Ifthis field is set to value ‘0’, SSD is not used.

The following field appears only if PHY_PROFILE is equal to ‘010’, whichindicates the advanced profile:

DP_MIMO: This 3-bit field indicates which type of MIMO encoding processis applied to the associated DP. The type of MIMO encoding process issignaled according to the table 17.

TABLE 17 Value MIMO encoding 000 FR-SM 001 FRFD-SM 010~111 reserved

DP_TI_TYPE: This 1-bit field indicates the type of time-interleaving. Avalue of ‘0’ indicates that one TI group corresponds to one frame andcontains one or more TI-blocks. A value of ‘1’ indicates that one TIgroup is carried in more than one frame and contains only one TI-block.

DP_TI_LENGTH: The use of this 2-bit field (the allowed values are only1, 2, 4, 8) is determined by the values set within the DP_TI_TYPE fieldas follows:

If the DP_TI_TYPE is set to the value ‘1’, this field indicates P_(I),the number of the frames to which each TI group is mapped, and there isone TI-block per TI group (N_(H)=1). The allowed P_(I) values with 2-bitfield are defined in the below table 18.

If the DP_TI_TYPE is set to the value ‘0’, this field indicates thenumber of TI-blocks N_(TI) per TI group, and there is one TI group perframe (P_(I)=1). The allowed P_(I) values with 2-bit field are definedin the below table 18.

TABLE 18 2-bit field P_(I) N_(TI) 00 1 1 01 2 2 10 4 3 11 8 4

DP_FRAME_INTERVAL: This 2-bit field indicates the frame interval(I_(JUMP)) within the frame-group for the associated DP and the allowedvalues are 1, 2, 4, 8 (the corresponding 2-bit field is ‘00’, ‘01’,‘10’, or ‘11’, respectively). For DPs that do not appear every frame ofthe frame-group, the value of this field is equal to the intervalbetween successive frames. For example, if a DP appears on the frames 1,5, 9, 13, etc., this field is set to ‘4’. For DPs that appear in everyframe, this field is set to ‘1’.

DP_TI_BYPASS: This 1-bit field determines the availability of timeinterleaver. If time interleaving is not used for a DP, it is set to‘1’. Whereas if time interleaving is used it is set to ‘0’.

DP_FIRST_FRAME_IDX: This 5-bit field indicates the index of the firstframe of the super-frame in which the current DP occurs. The value ofDP_FIRST_FRAME_IDX ranges from 0 to 31

DP_NUM_BLOCK_MAX: This 10-bit field indicates the maximum value ofDP_NUM_BLOCKS for this DP. The value of this field has the same range asDP_NUM_BLOCKS.

DP_PAYLOAD_TYPE: This 2-bit field indicates the type of the payload datacarried by the given DP. DP_PAYLOAD_TYPE is signaled according to thebelow table 19.

TABLE 19 Value Payload Type 00 TS. 01 IP 10 GS 11 reserved

DP_INBAND_MODE: This 2-bit field indicates whether the current DPcarries in-band signaling information. The in-band signaling type issignaled according to the below table 20.

TABLE 20 Value In-band mode 00 In-band signaling is not carried. 01INBAND-PLS is carried only 10 INBAND-ISSY is carried only 11 INBAND-PLSand INBAND-ISSY are carried

DP_PROTOCOL_TYPE: This 2-bit field indicates the protocol type of thepayload carried by the given DP. It is signaled according to the belowtable 21 when input payload types are selected.

TABLE 21 If If If DP_PAYLOAD_ DP_PAYLOAD_ DP_PAYLOAD_ TYPE TYPE TYPEValue Is TS Is IP Is GS 00 MPEG2-TS IPv4 (Note) 01 Reserved IPv6Reserved 10 Reserved Reserved Reserved 11 Reserved Reserved Reserved

DP_CRC_MODE: This 2-bit field indicates whether CRC encoding is used inthe Input Formatting block. The CRC mode is signaled according to thebelow table 22.

TABLE 22 Value CRC mode 00 Not used 01 CRC-8 10 CRC-16 11 CRC-32

DNP_MODE: This 2-bit field indicates the null-packet deletion mode usedby the associated DP when DP_PAYLOAD_TYPE is set to TS (‘00’). DNP_MODEis signaled according to the below table 23. If DP_PAYLOAD_TYPE is notTS (‘00’), DNP_MODE is set to the value ‘00’.

TABLE 23 Value Null-packet deletion mode 00 Not used 01 DNP-NORMAL 10DNP-OFFSET 11 reserved

ISSY_MODE: This 2-bit field indicates the ISSY mode used by theassociated DP when DP_PAYLOAD_TYPE is set to TS (‘00’). The ISSY_MODE issignaled according to the below table 24 If DP_PAYLOAD_TYPE is not TS(‘00’), ISSY_MODE is set to the value ‘00’.

TABLE 24 Value ISSY mode 00 Not used 01 ISSY-UP 10 ISSY-BBF 11 reserved

HC_MODE_TS: This 2-bit field indicates the TS header compression modeused by the associated DP when DP_PAYLOAD_TYPE is set to TS (‘00’). TheHC_MODE_TS is signaled according to the below table 25.

TABLE 25 Value Header compression mode 00 HC_MODE_TS 1 01 HC_MODE_TS 210 HC_MODE_TS 3 11 HC_MODE_TS 4

HC_MODE_IP: This 2-bit field indicates the IP header compression modewhen DP_PAYLOAD_TYPE is set to IP (‘01’). The HC_MODE_IP is signaledaccording to the below table 26.

TABLE 26 Value Header compression mode 00 No compression 01 HC_MODE_IP 110~11 reserved

PID: This 13-bit field indicates the PID number for TS headercompression when DP_PAYLOAD_TYPE is set to TS (‘00’) and HC_MODE_TS isset to ‘01’ or ‘10’.

RESERVED: This 8-bit field is reserved for future use.

The following field appears only if FIC_FLAG is equal to ‘1’:

FIC_VERSION: This 8-bit field indicates the version number of the FIC.

FIC_LENGTH_BYTE: This 13-bit field indicates the length, in bytes, ofthe FIC.

RESERVED: This 8-bit field is reserved for future use.

The following field appears only if AUX_FLAG is equal to ‘1’:

NUM_AUX: This 4-bit field indicates the number of auxiliary streams.Zero means no auxiliary streams are used.

AUX_CONFIG_RFU: This 8-bit field is reserved for future use.

AUX_STREAM_TYPE: This 4-bit is reserved for future use for indicatingthe type of the current auxiliary stream.

AUX_PRIVATE_CONFIG: This 28-bit field is reserved for future use forsignaling auxiliary streams.

FIG. 15 illustrates PLS2 data according to another embodiment of thepresent invention.

FIG. 15 illustrates PLS2-DYN data of the PLS2 data. The values of thePLS2-DYN data may change during the duration of one frame-group, whilethe size of fields remains constant.

The details of fields of the PLS2-DYN data are as follows:

FRAME_INDEX: This 5-bit field indicates the frame index of the currentframe within the super-frame. The index of the first frame of thesuper-frame is set to ‘0’.

PLS_CHANGE_COUNTER: This 4-bit field indicates the number ofsuper-frames ahead where the configuration will change. The nextsuper-frame with changes in the configuration is indicated by the valuesignaled within this field. If this field is set to the value ‘0000’, itmeans that no scheduled change is foreseen: e.g., value ‘1’ indicatesthat there is a change in the next super-frame.

FIC_CHANGE_COUNTER: This 4-bit field indicates the number ofsuper-frames ahead where the configuration (i.e., the contents of theFIC) will change. The next super-frame with changes in the configurationis indicated by the value signaled within this field. If this field isset to the value ‘0000’, it means that no scheduled change is foreseen:e.g. value ‘0001’ indicates that there is a change in the nextsuper-frame.

RESERVED: This 16-bit field is reserved for future use.

The following fields appear in the loop over NUM_DP, which describe theparameters associated with the DP carried in the current frame.

DP_ID: This 6-bit field indicates uniquely the DP within a PHY profile.

DP_START: This 15-bit (or 13-bit) field indicates the start position ofthe first of the DPs using the DPU addressing scheme. The DP_START fieldhas differing length according to the PHY profile and FFT size as shownin the below table 27.

TABLE 27 DP_START field size PHY profile 64K 16K Base 13 bit 15 bitHandheld — 13 bit Advanced 13 bit 15 bit

DP_NUM_BLOCK: This 10-bit field indicates the number of FEC blocks inthe current TI group for the current DP. The value of DP_NUM_BLOCKranges from 0 to 1023

RESERVED: This 8-bit field is reserved for future use.

The following fields indicate the FIC parameters associated with theEAC.

EAC_FLAG: This 1-bit field indicates the existence of the EAC in thecurrent frame. This bit is the same value as the EAC_FLAG in thepreamble.

EAS_WAKE_UP_VERSION_NUM: This 8-bit field indicates the version numberof a wake-up indication.

If the EAC_FLAG field is equal to ‘1’, the following 12 bits areallocated for EAC_LENGTH_BYTE field. If the EAC_FLAG field is equal to‘0’, the following 12 bits are allocated for EAC_COUNTER.

EAC_LENGTH_BYTE: This 12-bit field indicates the length, in byte, of theEAC.

EAC_COUNTER: This 12-bit field indicates the number of the frames beforethe frame where the EAC arrives.

The following field appears only if the AUX_FLAG field is equal to ‘1’:

AUX_PRIVATE_DYN: This 48-bit field is reserved for future use forsignaling auxiliary streams. The meaning of this field depends on thevalue of AUX_STREAM_TYPE in the configurable PLS2-STAT.

CRC_32: A 32-bit error detection code, which is applied to the entirePLS2.

FIG. 16 illustrates a logical structure of a frame according to anembodiment of the present invention.

As above mentioned, the PLS, EAC, FIC, DPs, auxiliary streams and dummycells are mapped into the active carriers of the OFDM symbols in theframe. The PLS1 and PLS2 are first mapped into one or more FSS(s). Afterthat, EAC cells, if any, are mapped immediately following the PLS field,followed next by FIC cells, if any. The DPs are mapped next after thePLS or EAC, FIC, if any. Type 1 DPs follows first, and Type 2 DPs next.The details of a type of the DP will be described later. In some case,DPs may carry some special data for EAS or service signaling data. Theauxiliary stream or streams, if any, follow the DPs, which in turn arefollowed by dummy cells. Mapping them all together in the abovementioned order, i.e. PLS, EAC, FIC, DPs, auxiliary streams and dummydata cells exactly fill the cell capacity in the frame.

FIG. 17 illustrates PLS mapping according to an embodiment of thepresent invention.

PLS cells are mapped to the active carriers of FSS(s). Depending on thenumber of cells occupied by PLS, one or more symbols are designated asFSS(s), and the number of FSS(s) N_(FSS) is signaled by NUM_FSS in PLS1.The FSS is a special symbol for carrying PLS cells. Since robustness andlatency are critical issues in the PLS, the FSS(s) has higher density ofpilots allowing fast synchronization and frequency-only interpolationwithin the FSS.

PLS cells are mapped to active carriers of the N_(FSS) FSS(s) in atop-down manner as shown in an example in FIG. 17. The PLS1 cells aremapped first from the first cell of the first FSS in an increasing orderof the cell index. The PLS2 cells follow immediately after the last cellof the PLS1 and mapping continues downward until the last cell index ofthe first FSS. If the total number of required PLS cells exceeds thenumber of active carriers of one FSS, mapping proceeds to the next FSSand continues in exactly the same manner as the first FSS.

After PLS mapping is completed, DPs are carried next. If EAC, FIC orboth are present in the current frame, they are placed between PLS and“normal” DPs.

FIG. 18 illustrates EAC mapping according to an embodiment of thepresent invention.

EAC is a dedicated channel for carrying EAS messages and links to theDPs for EAS. EAS support is provided but EAC itself may or may not bepresent in every frame. EAC, if any, is mapped immediately after thePLS2 cells. EAC is not preceded by any of the FIC, DPs, auxiliarystreams or dummy cells other than the PLS cells. The procedure ofmapping the EAC cells is exactly the same as that of the PLS.

The EAC cells are mapped from the next cell of the PLS2 in increasingorder of the cell index as shown in the example in FIG. 18. Depending onthe EAS message size, EAC cells may occupy a few symbols, as shown inFIG. 18.

EAC cells follow immediately after the last cell of the PLS2, andmapping continues downward until the last cell index of the last FSS. Ifthe total number of required EAC cells exceeds the number of remainingactive carriers of the last FSS mapping proceeds to the next symbol andcontinues in exactly the same manner as FSS(s). The next symbol formapping in this case is the normal data symbol, which has more activecarriers than a FSS.

After EAC mapping is completed, the FIC is carried next, if any exists.If FIC is not transmitted (as signaled in the PLS2 field), DPs followimmediately after the last cell of the EAC.

FIG. 19 illustrates FIC mapping according to an embodiment of thepresent invention.

(a) shows an example mapping of FIC cell without EAC and (b) shows anexample mapping of FIC cell with EAC.

FIC is a dedicated channel for carrying cross-layer information toenable fast service acquisition and channel scanning. This informationprimarily includes channel binding information between DPs and theservices of each broadcaster. For fast scan, a receiver can decode FICand obtain information such as broadcaster ID, number of services, andBASE_DP_ID. For fast service acquisition, in addition to FIC, base DPcan be decoded using BASE_DP_ID. Other than the content it carries, abase DP is encoded and mapped to a frame in exactly the same way as anormal DP. Therefore, no additional description is required for a baseDP. The FIC data is generated and consumed in the Management Layer. Thecontent of FIC data is as described in the Management Layerspecification.

The FIC data is optional and the use of FIC is signaled by the FIC_FLAGparameter in the static part of the PLS2. If FIC is used, FIC_FLAG isset to ‘1’ and the signaling field for FIC is defined in the static partof PLS2. Signaled in this field are FIC_VERSION, and FIC_LENGTH_BYTE.FIC uses the same modulation, coding and time interleaving parameters asPLS2. FIC shares the same signaling parameters such as PLS2_MOD andPLS2_FEC. FIC data, if any, is mapped immediately after PLS2 or EAC ifany. FIC is not preceded by any normal DPs, auxiliary streams or dummycells. The method of mapping FIC cells is exactly the same as that ofEAC which is again the same as PLS.

Without EAC after PLS, FIC cells are mapped from the next cell of thePLS2 in an increasing order of the cell index as shown in an example in(a). Depending on the FIC data size, FIC cells may be mapped over a fewsymbols, as shown in (b).

FIC cells follow immediately after the last cell of the PLS2, andmapping continues downward until the last cell index of the last FSS. Ifthe total number of required FIC cells exceeds the number of remainingactive carriers of the last FSS, mapping proceeds to the next symbol andcontinues in exactly the same manner as FSS(s). The next symbol formapping in this case is the normal data symbol which has more activecarriers than a FSS.

If EAS messages are transmitted in the current frame, EAC precedes FIC,and FIC cells are mapped from the next cell of the EAC in an increasingorder of the cell index as shown in (b).

After FIC mapping is completed, one or more DPs are mapped, followed byauxiliary streams, if any, and dummy cells.

FIG. 20 illustrates a type of DP according to an embodiment of thepresent invention.

(a) shows type 1 DP and (b) shows type 2 DP.

After the preceding channels, i.e., PLS, EAC and FIC, are mapped, cellsof the DPs are mapped. A DP is categorized into one of two typesaccording to mapping method:

Type 1 DP: DP is mapped by TDM

Type 2 DP: DP is mapped by FDM

The type of DP is indicated by DP_TYPE field in the static part of PLS2.FIG. 20 illustrates the mapping orders of Type 1 DPs and Type 2 DPs.Type 1 DPs are first mapped in the increasing order of cell index, andthen after reaching the last cell index, the symbol index is increasedby one. Within the next symbol, the DP continues to be mapped in theincreasing order of cell index starting from p=0. With a number of DPsmapped together in one frame, each of the Type 1 DPs are grouped intime, similar to TDM multiplexing of DPs.

Type 2 DPs are first mapped in the increasing order of symbol index, andthen after reaching the last OFDM symbol of the frame, the cell indexincreases by one and the symbol index rolls back to the first availablesymbol and then increases from that symbol index. After mapping a numberof DPs together in one frame, each of the Type 2 DPs are grouped infrequency together, similar to FDM multiplexing of DPs.

Type 1 DPs and Type 2 DPs can coexist in a frame if needed with onerestriction; Type 1 DPs always precede Type 2 DPs. The total number ofOFDM cells carrying Type 1 and Type 2 DPs cannot exceed the total numberof OFDM cells available for transmission of DPs:D _(DP1) +D _(DP2) ≦D _(DP)  [Expression 2]

where D_(DP1) is the number of OFDM cells occupied by Type 1 DPs,D_(DP2) is the number of cells occupied by Type 2 DPs. Since PLS, EAC,FIC are all mapped in the same way as Type 1 DP, they all follow “Type 1mapping rule”. Hence, overall, Type 1 mapping always precedes Type 2mapping.

FIG. 21 illustrates DP mapping according to an embodiment of the presentinvention.

(a) shows an addressing of OFDM cells for mapping type 1 DPs and (b)shows an an addressing of OFDM cells for mapping for type 2 DPs.

Addressing of OFDM cells for mapping Type 1 DPs (0, . . . , D_(DP1)−1)is defined for the active data cells of Type 1 DPs. The addressingscheme defines the order in which the cells from the TIs for each of theType 1 DPs are allocated to the active data cells. It is also used tosignal the locations of the DPs in the dynamic part of the PLS2.

Without EAC and FIC, address 0 refers to the cell immediately followingthe last cell carrying PLS in the last FSS. If EAC is transmitted andFIC is not in the corresponding frame, address 0 refers to the cellimmediately following the last cell carrying EAC. If FIC is transmittedin the corresponding frame, address 0 refers to the cell immediatelyfollowing the last cell carrying FIC. Address 0 for Type 1 DPs can becalculated considering two different cases as shown in (a). In theexample in (a), PLS, EAC and FIC are assumed to be all transmitted.Extension to the cases where either or both of EAC and FIC are omittedis straightforward. If there are remaining cells in the FSS aftermapping all the cells up to FIC as shown on the left side of (a).

Addressing of OFDM cells for mapping Type 2 DPs (0, D_(D)p₂−1) isdefined for the active data cells of Type 2 DPs. The addressing schemedefines the order in which the cells from the TIs for each of the Type 2DPs are allocated to the active data cells. It is also used to signalthe locations of the DPs in the dynamic part of the PLS2.

Three slightly different cases are possible as shown in (b). For thefirst case shown on the left side of (b), cells in the last FSS areavailable for Type 2 DP mapping. For the second case shown in themiddle, FIC occupies cells of a normal symbol, but the number of FICcells on that symbol is not larger than C_(FSS). The third case, shownon the right side in (b), is the same as the second case except that thenumber of FIC cells mapped on that symbol exceeds C_(FSS).

The extension to the case where Type 1 DP(s) precede Type 2 DP(s) isstraightforward since PLS, EAC and FIC follow the same “Type 1 mappingrule” as the Type 1 DP(s).

A data pipe unit (DPU) is a basic unit for allocating data cells to a DPin a frame.

A DPU is defined as a signaling unit for locating DPs in a frame. A CellMapper 7010 may map the cells produced by the TIs for each of the DPs. ATime interleaver 5050 outputs a series of TI-blocks and each TI-blockcomprises a variable number of XFECBLOCKs which is in turn composed of aset of cells. The number of cells in an XFECBLOCK, N_(cells), isdependent on the FECBLOCK size, N_(ldpc), and the number of transmittedbits per constellation symbol. A DPU is defined as the greatest commondivisor of all possible values of the number of cells in a XFECBLOCK,N_(cells), supported in a given PHY profile. The length of a DPU incells is defined as L_(DPU). Since each PHY profile supports differentcombinations of FECBLOCK size and a different number of bits perconstellation symbol, L_(DPU) is defined on a PHY profile basis.

FIG. 22 illustrates an FEC structure according to an embodiment of thepresent invention.

FIG. 22 illustrates an FEC structure according to an embodiment of thepresent invention before bit interleaving. As above mentioned, Data FECencoder may perform the FEC encoding on the input BBF to generateFECBLOCK procedure using outer coding (BCH), and inner coding (LDPC).The illustrated FEC structure corresponds to the FECBLOCK. Also, theFECBLOCK and the FEC structure have same value corresponding to a lengthof LDPC codeword.

The BCH encoding is applied to each BBF (K_(bch) bits), and then LDPCencoding is applied to BCH-encoded BBF (K_(ldpc) bits=N_(bch) bits) asillustrated in FIG. 22.

The value of N_(ldpc) is either 64800 bits (long FECBLOCK) or 16200 bits(short FECBLOCK).

The below table 28 and table 29 show FEC encoding parameters for a longFECBLOCK and a short FECBLOCK, respectively.

TABLE 28 BCH error LDPC correction Rate N_(ldpc) K_(ldpc) K_(bch)capability N_(bch) − K_(bch) 5/15 64800 21600 21408 12 192 6/15 2592025728 7/15 30240 30048 8/15 34560 34368 9/15 38880 38688 10/15  4320043008 11/15  47520 47328 12/15  51840 51648 13/15  56160 55968

TABLE 29 BCH error LDPC correction Rate N_(ldpc) K_(ldpc) K_(bch)capability N_(bch) − K_(bch) 5/15 16200 5400 5232 12 168 6/15 6480 63127/15 7560 7392 8/15 8640 8472 9/15 9720 9552 10/15  10800 10632 11/15 11880 11712 12/15  12960 12792 13/15  14040 13872

The details of operations of the BCH encoding and LDPC encoding are asfollows:

A 12-error correcting BCH code is used for outer encoding of the BBF.The BCH generator polynomial for short FECBLOCK and long FECBLOCK areobtained by multiplying together all polynomials.

LDPC code is used to encode the output of the outer BCH encoding. Togenerate a completed B_(ldpc) (FECBLOCK), P_(ldpc) (parity bits) isencoded systematically from each I_(ldpc) (BCH-encoded BBF), andappended to I_(ldpc). The completed B_(ldpc) (FECBLOCK) are expressed asfollow Expression.B _(ldpc) =[I _(ldpc) P _(ldpc) ]=[i ₀ , i ₁ , . . . , i _(K) _(ldpc) ⁻¹, p ₀ , p ₁ , . . . , p _(N) _(ldpc) _(−K) _(ldpc) ⁻¹]  [Expression 3]

The parameters for long FECBLOCK and short FECBLOCK are given in theabove table 28 and 29, respectively.

The detailed procedure to calculate N_(ldpc)−K_(ldpc) parity bits forlong FECBLOCK, is as follows:

1) Initialize the parity bits,p ₀ =p ₁ =p ₂ =. . . =p _(N) _(ldpc) _(−K) _(ldpc) ⁻¹=0  [Expression 4]

2) Accumulate the first information bit-i₀, at parity bit addressesspecified in the first row of an addresses of parity check matrix. Thedetails of addresses of parity check matrix will be described later. Forexample, for rate 13/15:p ₉₈₃ =p ₉₈₃ ⊕i ₀ p ₂₈₁₅ =p ₂₈₁₅ ⊕i ₀p ₄₈₃₇ =p ₄₈₃₇ ⊕i ₀ p ₄₉₈₉ =p ₄₉₈₉ ⊕i ₀p ₆₁₃₈ =p ₆₁₃₈ ⊕i ₀ p ₆₄₅₈ =p ₆₄₅₃ ⊕i ₀p ₆₉₂₁ =p ₆₉₂₁ ⊕i ₀ p ₆₉₇₄ =p ₆₉₇₄ ⊕i ₀p ₇₅₇₂ =p ₇₅₇₂ ⊕i ₀ p ₈₂₆₀ =p ₈₂₆₀ ⊕i ₀p ₈₄₉₆ =p ₈₄₉₆ ⊕i ₀  [Expression 5]

3) For the next 359 information bits, i_(s), s=1, 2, . . . , 359accumulate i_(s) at parity bit addresses using following Expression.{x+(s mod 360)×Q _(ldpc)}mod(N _(ldpc) −K _(ldpc))  [Expression 6]

where x denotes the address of the parity bit accumulator correspondingto the first bit i₀, and Q_(ldpc) is a code rate dependent constantspecified in the addresses of parity check matrix. Continuing with theexample, Q_(ldpc)=24 for rate 13/15, so for information bit i₁, thefollowing operations are performed:p ₁₀₀₇ =p ₁₀₀₇ ⊕i ₁ p ₂₈₃₉ =p ₂₈₃₉ ⊕i ₁p ₄₈₆₁ =p ₄₈₆₁ ⊕i ₁ p ₅₀₁₃ =p ₅₀₁₃ ⊕i ₁p ₆₁₆₂ =p ₆₁₆₂ ⊕i ₁ p ₆₄₈₇ =p ₆₄₈₂ ⊕i ₁p ₆₉₄₅ =p ₆₉₄₅ ⊕i ₁ p ₆₉₉₈ =p ₆₉₉₈ ⊕i ₁p ₇₅₉₆ =p ₇₅₉₆ ⊕i ₁ p ₈₇₈₄ =p ₈₂₈₄ ⊕i ₁p ₈₅₂₀ =p ₈₅₂₀ ⊕i ₁  [Expression 7]

4) For the 361^(st) information bit i₃₆₀, the addresses of the paritybit accumulators are given in the second row of the addresses of paritycheck matrix. In a similar manner the addresses of the parity bitaccumulators for the following 359 information bits i_(s), s=361, 362, .. . , 719 are obtained using the Expression 6, where x denotes theaddress of the parity bit accumulator corresponding to the informationbit i₃₆₀, i.e., the entries in the second row of the addresses of paritycheck matrix.

5) In a similar manner, for every group of 360 new information bits, anew row from addresses of parity check matrixes used to find theaddresses of the parity bit accumulators.

After all of the information bits are exhausted, the final parity bitsare obtained as follows:

6) Sequentially perform the following operations starting with i=1p _(i) =p _(i) ⊕p _(i−1) , i=1, 2, . . . , N _(ldpc) −K_(ldpc)−1  [Expression 8]

where final content of p_(i), i=0, 1, . . . , K_(ldpc)−1 is equal to theparity bit p_(i).

TABLE 30 Code Rate Q_(ldpc) 5/15 120 6/15 108 7/15 96 8/15 84 9/15 7210/15  60 11/15  48 12/15  36 13/15  24

This LDPC encoding procedure for a short FECBLOCK is in accordance witht LDPC encoding procedure for the long FECBLOCK, except replacing thetable 30 with table 31, and replacing the addresses of parity checkmatrix for the long FECBLOCK with the addresses of parity check matrixfor the short FECBLOCK.

TABLE 31 Code Rate Q_(ldpc) 5/15 30 6/15 27 7/15 24 8/15 21 9/15 1810/15  15 11/15  12 12/15  9 13/15  6

FIG. 23 illustrates a bit interleaving according to an embodiment of thepresent invention.

The outputs of the LDPC encoder are bit-interleaved, which consists ofparity interleaving followed by Quasi-Cyclic Block (QCB) interleavingand inner-group interleaving.

(a) shows Quasi-Cyclic Block (QCB) interleaving and (b) showsinner-group interleaving.

The FECBLOCK may be parity interleaved. At the output of the parityinterleaving, the LDPC codeword consists of 180 adjacent QC blocks in along FECBLOCK and 45 adjacent QC blocks in a short FECBLOCK. Each QCblock in either a long or short FECBLOCK consists of 360 bits. Theparity interleaved LDPC codeword is interleaved by QCB interleaving. Theunit of QCB interleaving is a QC block. The QC blocks at the output ofparity interleaving are permutated by QCB interleaving as illustrated inFIG. 23, where N_(cells)=64800/η_(mod) or 16200/η_(mod) according to theFECBLOCK length. The QCB interleaving pattern is unique to eachcombination of modulation type and LDPC code rate.

After QCB interleaving, inner-group interleaving is performed accordingto modulation type and order (η_(mod)) which is defined in the belowtable 32. The number of QC blocks for one inner-group, N_(QCB) _(_)_(IG), is also defined.

TABLE 32 Modulation type η_(mod) N_(QCB)_IG QAM-16 4 2 NUC-16 4 4 NUQ-646 3 NUC-64 6 6 NUQ-256 8 4 NUC-256 8 8 NUQ-1024 10 5 NUC-1024 10 10

The inner-group interleaving process is performed with N_(QCB) _(_)_(IG) QC blocks of the QCB interleaving output. Inner-group interleavinghas a process of writing and reading the bits of the inner-group using360 columns and N_(QCB) _(_) _(IG) rows. In the write operation, thebits from the QCB interleaving output are written row-wise. The readoperation is performed column-wise to read out m bits from each row,where m is equal to 1 for NUC and 2 for NUQ.

FIG. 24 illustrates a cell-word demultiplexing according to anembodiment of the present invention.

(a) shows a cell-word demultiplexing for 8 and 12 bpcu MIMO and (b)shows a cell-word demultiplexing for 10 bpcu MIMO.

Each cell word (c_(0,l), c_(1,l), . . . , c_(ηmod−1,l)) of the bitinterleaving output is demultiplexed into (d_(1,0,m), d_(1,1,m) . . . ,d_(1,ηmod−1, m)) and (d_(2,0,m), d_(2,1,m) . . . , d_(2,ηmod−1,m)) asshown in (a), which describes the cell-word demultiplexing process forone XFECBLOCK.

For the 10 bpcu MIMO case using different types of NUQ for MIMOencoding, the Bit Interleaver for NUQ-1024 is re-used. Each cell word(c_(0,l), c_(1,l), . . . , c_(9,l)) of the Bit Interleaver output isdemultiplexed into (d_(1,0,m), d_(1,1,m) . . . , d_(1,3,m)) and(d_(2,0,m), d_(2,1,m) . . . , d_(2,5,m)), as shown in (b).

FIG. 25 illustrates a time interleaving according to an embodiment ofthe present invention.

(a) to (c) show examples of TI mode.

The time interleaver operates at the DP level. The parameters of timeinterleaving (TI) may be set differently for each DP.

The following parameters, which appear in part of the PLS2-STAT data,configure the TI:

DP_TI_TYPE (allowed values: 0 or 1): Represents the TI mode; ‘0’indicates the mode with multiple TI blocks (more than one TI block) perTI group. In this case, one TI group is directly mapped to one frame (nointer-frame interleaving). ‘1’ indicates the mode with only one TI blockper TI group. In this case, the TI block may be spread over more thanone frame (inter-frame interleaving).

DP_TI_LENGTH: If DP_TI_TYPE=‘0’, this parameter is the number of TIblocks N_(TI) per TI group. For DP_TI_TYPE=‘1’, this parameter is thenumber of frames P_(i) spread from one TI group.

DP_NUM_BLOCK_MAX (allowed values: 0 to 1023): Represents the maximumnumber of XFECBLOCKs per TI group.

DP_FRAME_INTERVAL (allowed values: 1, 2, 4, 8): Represents the number ofthe frames L_(ump) between two successive frames carrying the same DP ofa given PHY profile.

DP_TI_BYPASS (allowed values: 0 or 1): If time interleaving is not usedfor a DP, this parameter is set to ‘1’. It is set to ‘0’ if timeinterleaving is used.

Additionally, the parameter DP_NUM_BLOCK from the PLS2-DYN data is usedto represent the number of XFECBLOCKs carried by one TI group of the DP.

When time interleaving is not used for a DP, the following TI group,time interleaving operation, and TI mode are not considered. However,the Delay Compensation block for the dynamic configuration informationfrom the scheduler will still be required. In each DP, the XFECBLOCKsreceived from the SSD/MIMO encoding are grouped into TI groups. That is,each TI group is a set of an integer number of XFECBLOCKs and willcontain a dynamically variable number of XFECBLOCKs. The number ofXFECBLOCKs in the TI group of index n is denoted by N_(xBLOCK) _(_)_(Group)(n) and is signaled as DP_NUM_BLOCK in the PLS2-DYN data. Notethat N_(xBLOCK) _(_) _(Group)(n) may vary from the minimum value of 0 tothe maximum value N_(xBLOCK) _(_) _(Group) _(_) _(MAX) (corresponding toDP_NUM_BLOCK_MAX) of which the largest value is 1023.

Each TI group is either mapped directly onto one frame or spread overP_(I) frames. Each TI group is also divided into more than one TI blocks(N_(TI)), where each TI block corresponds to one usage of timeinterleaver memory. The TI blocks within the TI group may containslightly different numbers of XFECBLOCKs. If the TI group is dividedinto multiple TI blocks, it is directly mapped to only one frame. Thereare three options for time interleaving (except the extra option ofskipping the time interleaving) as shown in the below table 33.

TABLE 33 Modes Descriptions Option-1 Each TI group contains one TI blockand is mapped directly to one frame as shown in (a). This option issignaled in the PLS2-STAT by DP_TI_TYPE = ‘0’ and DP_TI_LENGTH =‘1’(N_(TI) = 1). Option-2 Each TI group contains one TI block and ismapped to more than one frame. (b) shows an example, where one TI groupis mapped to two frames, i.e., DP_TI_LENGTH = ‘2’ (P_(I) = 2) andDP_FRAME_INTERVAL (I_(JUMP) = 2). This provides greater time diversityfor low data-rate services. This option is signaled in the PLS2-STAT byDP_TI_TYPE = ‘1’. Option-3 Each TI group is divided into multiple TIblocks and is mapped directly to one frame as shown in (c). Each TIblock may use full TI memory, so as to provide the maximum bit-rate fora DP. This option is signaled in the PLS2-STAT signaling by DP_TI_TYPE =‘0’ and DP_TI_LENGTH = N_(TI), while P_(I) = 1.

In each DP, the TI memory stores the input XFECBLOCKs (output XFECBLOCKsfrom the SSD/MIMO encoding block). Assume that input XFECBLOCKs aredefined as

(d_(n,s,0,0), d_(n,s,0,1), . . . , d_(n,s,0,N) _(cells) ⁻¹, d_(n,s,1,0),. . . , d_(n,s,1,N) _(cells) ⁻¹, . . . , d_(n,s,N) _(xBLOCK_TI)_((n,s)−1), . . . , d_(n,s,N) _(xBLOCK_TI) _((n,s)−1,N) _(cells) ⁻¹),

where d_(n,s,r,q) is the qth cell of the rth XFECBLOCK in the sth TIblock of the nth TI group and represents the outputs of SSD and MIMOencodings as follows. dn,s,r,q={_(g) _(n,s,r,q)_(, the output of MIMO encoding) ^(f) ^(n,s,r,q)^(, the output of SSD encoding)

In addition, assume that output XFECBLOCKs from the time interleaver aredefined as

(h_(n,s,0),h_(n,s,1), . . . ,h_(n,s,i), . . . h_(n,s,N) _(xBLOCK) _(—TI)_((n,s)×N) _(cells) ⁻¹)

where h_(n,s,i) is the ith output cell (for i=0, . . . , N_(xBLOCK) _(_)_(TI)(n,s)×N_(cells)−1) in the sth TI block of the nth TI group.

Typically, the time interleaver will also act as a buffer for DP dataprior to the process of frame building. This is achieved by means of twomemory banks for each DP. The first TI-block is written to the firstbank. The second TI-block is written to the second bank while the firstbank is being read from and so on.

The TI is a twisted row-column block interleaver. For the sth TI blockof the nth TI group, the number of rows N_(r) of a TI memory is equal tothe number of cells N_(cells), i.e., N_(r)=N_(cells) while the number ofcolumns N_(c) is equal to the number N_(xBLOCK) _(_) _(TI) (n,s).

FIG. 26 illustrates the basic operation of a twisted row-column blockinterleaver according to an embodiment of the present invention.

shows a writing operation in the time interleaver and (b) shows areading operation in the time interleaver The first XFECBLOCK is writtencolumn-wise into the first column of the TI memory, and the secondXFECBLOCK is written into the next column, and so on as shown in (a).Then, in the interleaving array, cells are read out diagonal-wise.During diagonal-wise reading from the first row (rightwards along therow beginning with the left-most column) to the last row, N_(r) cellsare read out as shown in (b). In detail, assuming z_(n,s,i) (i=0, . . ., N_(r)N_(c)) as the TI memory cell position to be read sequentially,the reading process in such an interleaving array is performed bycalculating the row index R_(n,s,i), the column index C_(n,s,i), and theassociated twisting parameter T_(n,s,i) as follows expression.

$\begin{matrix}{{{GENERATE}\left( {R_{n,s,i},C_{n,s,i}} \right)} = \left\{ {{R_{n,s,i} = {{mod}\left( {i,N_{r}} \right)}},{T_{n,s,i} = {{mod}\left( {{S_{shift} \times R_{n,s,i}},N_{c}} \right)}},{C_{n,s,i} = {{mod}\left( {{T_{n,s,i} + \left\lfloor \frac{i}{N_{r}} \right\rfloor},N_{c}} \right)}}} \right\}} & \left\lbrack {{Expression}\mspace{14mu} 9} \right\rbrack\end{matrix}$

where S_(shift) is a common shift value for the diagonal-wise readingprocess regardless of N_(xBLOCK) _(_) _(TI) (n, s) and it is determinedby N_(xBLOCK) _(_) _(TI) _(_) _(MAX) given in the PLS2-STAT as followsexpression.

$\begin{matrix}{{for}\left\{ {\begin{matrix}{{N_{{xBLOCK}\;\_\;{TI}\;\_\;{MAX}}^{\prime} = {N_{{xBLOCK}\;\_\;{TI}\;\_\;{MAX}} + 1}},} & {{{if}\mspace{14mu} N_{{xBLOCK}\;\_\;{TI}\;\_\;{MAX}}{mod}\; 2} = 0} \\{{N_{{xBLOCK}\;\_\;{TI}\;\_\;{MAX}}^{\prime} = N_{{xBLOCK}\;\_\;{TI}\;\_\;{MAX}}},} & {{{if}\mspace{14mu} N_{{xBLOCK}\;\_\;{TI}\;\_\;{MAX}}{mod}\; 2} = 1}\end{matrix},\mspace{79mu}{S_{shift} = \frac{N_{{xBLOCK}\;\_\;{TI}\;\_\;{MAX}}^{\prime} - 1}{2}}} \right.} & \left\lbrack {{Expression}\mspace{14mu} 10} \right\rbrack\end{matrix}$

As a result, the cell positions to be read are calculated by acoordinate as

FIG. 27 illustrates an operation of a twisted row-column blockinterleaver according to another embodiment of the present invention.

More specifically, FIG. 27 illustrates the interleaving array in the TImemory for each

TI group, including virtual XFECBLOCKs when N_(xBLOCK) _(_) _(TI) (0,0)=3, N_(xBLOCK) _(_) _(TI) (1,0)=6, N_(xBLOCK) _(_) _(TI) (2,0)=5.

The variable number N_(xBLOCK) _(_) _(TI)(n, s)=N_(r) will be less thanor equal to N′_(xBLOCK) _(_) _(TI) _(_) _(MAX). Thus, in order toachieve a single-memory deinterleaving at the receiver side, regardlessof N_(xBLOCK) _(_) _(TI)(n, s), the interleaving array for use in atwisted row-column block interleaver is set to the size ofN_(r)×N_(c)=N_(cells)×N′_(xBLOCK) _(_) _(TI) _(_) _(MAX) by insertingthe virtual XFECBLOCKs into the TI memory and the reading process isaccomplished as follow expression.

p = 0; [Expression 11] for i = 0;i < N_(cells)N′_(xBLOCK)_TI_MAX;i = i +1 {GENERATE (R_(n,s,i),C_(n,s,i)); V_(i) = N_(r)C_(n,s,j) + R_(n,s,j) if V_(i) < N_(cells)N_(xBLOCK)_TI(n,s)  {   Z_(n,s,p) = V_(i); p = p +1;   } }

The number of TI groups is set to 3. The option of time interleaver issignaled in the PLS2-STAT data by DP_TI_TYPE=‘0’, DP_FRAME_INTERVAL=‘1’,and DP_TI_LENGTH=‘1’, I_(JUMP)=1, and P_(I)=1. The number of XFECBLOCKs,each of which has N_(cells)=30 cells, per TI group is signaled in thePLS2-DYN data by N_(xBLOCK) _(_) _(TI)(0,0)=3, N_(xBLOCK) _(_)_(TI)(1,0)=6, and N_(xBLOCK) _(_) _(TI)(2,0)=5, respectively. Themaximum number of XFECBLOCK is signaled in the PLS2-STAT data byN_(xBLOCK) _(_) _(Group) _(_) _(MAX), which leads to └N_(xBLOCK) _(_)_(Group) _(_) _(MAX)/N_(TI)┘=N_(xBLOCK) _(_) _(TI) _(_) _(MAX)=6.

FIG. 28 illustrates a diagonal-wise reading pattern of a twistedrow-column block interleaver according to an embodiment of the presentinvention.

More specifically FIG. 28 shows a diagonal-wise reading pattern fromeach interleaving array with parameters of N′_(xBLOCK) _(_) _(TI) _(_)_(MAX)=7 and S_(Shift)=(7−1)/2=3. Note that in the reading process shownas pseudocode above, if V_(i)≧N_(cells)N_(xBLOCK) _(_) _(TI)(n,s) thevalue of V_(i) is skipped and the next calculated value of V_(i) isused.

FIG. 29 illustrates interlaved XFECBLOCKs from each interleaving arrayaccording to an embodiment of the present invention.

FIG. 29 illustrates the interleaved XFECBLOCKs from each interleavingarray with parameters of N′_(xBLOCK) _(_) _(TI) _(_) _(MAX)=7 andS_(shift)=3.

FIG. 30 illustrates a frame structure of a broadcast system according toan embodiment of the present invention.

A cell mapper included in the aforementioned frame structure module mayarrange cells transmitting input DP data processed according to SISO,MISO or MIMO, cells transmitting common DP and cells transmitting PLSdata in a signal frame according to scheduling information. Then,generated signal frames may be continuously transmitted.

A broadcast signal transmission apparatus and method according to anembodiment of the present invention can multiplex different signals of abroadcast transmission/reception system in the same RF channel andtransmit the multiplexed signals and a broadcast signal receptionapparatus and method according to an embodiment of the present inventioncan process the signals. Accordingly, the present invention can providea flexible broadcast transmission/reception system.

The broadcast signal transmission apparatus according to an embodimentof the present invention can continuously transmit a plurality ofsuperframes carrying data related to a broadcast service.

FIG. 30(a) illustrates a superframe according to an embodiment of thepresent invention. The duration of the superframe can be represented byTsuper_frame. As shown in FIG. 30(b), the superframe may include aplurality of frame type sets and non-compatible frames (NCFs). A signalframe according to an embodiment of the present invention is a TDM (TimeDivision Multiplexing) signal frame at a physical layer, generated inthe aforementioned frame structure module, and the NCF is a frame thatcan be used for new broadcast service systems in future.

The superframe according to an embodiment of the present invention mayinclude 8 frame type sets. A frame type set may be referred to as aframe repetition unit (FRU). The FRU is a basic multiplexing unit forTDM of a signal frame.

FIG. 30(c) illustrates a configuration of the frame type set accordingto an embodiment of the present invention. Each frame type set mayinclude a plurality of frames.

Signal frames according to an embodiment of the present invention cantransmit different services. Each signal frame according to anembodiment of the present invention transmits one of UD (Ultra highDefinition) service, mobile service or HD (High Definition) service.Signal frames have different durations Tframe1, Tframe2, and Tframe3depending on transmitted services. As shown in FIG. 30, a signal frametransmitting UD service may be referred to as frame type 1 having aduration of 250 msec. A signal frame transmitting mobile service may bereferred to as frame type 2 having a duration of 125 msec. A signalframe transmitting HD service may be referred to as frame type 3 havinga duration of 250 msec.

The names of signal frames, types of services transmitted by the signalframes and durations of the signal frames, suggested in the presentinvention, are exemplary and may be changed according to designer.

The signal frame according to an embodiment of the present invention maytransmit data for one of a base profile, handheld profile and advancedprofile. That is, data corresponding to each profile can be transmittedon a signal frame basis. The broadcast signal reception apparatus mayidentify each profile according to a received signal frame and obtain abroadcast service suitable therefor. One frame type set may include aplurality of signal frames corresponding to the same profile. This maybe changed according to designer.

FIG. 30(d) illustrates a configuration of each signal frame. Each signalframe may include a preamble, edge pilot, signaling field and aplurality of data symbols. This configuration may be changed accordingto designer.

The preamble is located at the head of the signal frame and may carrybasic transmission parameters for identifying a broadcast system andtype of each signal frame, information for synchronization of the timedomain and frequency domain, information related to EAS (Emergency AlertSystem) messages (or EAC messages) and the like. The broadcast signalreception apparatus according to an embodiment of the present inventioncan perform frame synchronization since the broadcast signal receptionapparatus can detect the preamble to acquire the frame start point.

The preamble according to an embodiment of the present invention is abasic transmission parameter and may include type of profile transmittedthrough a signal frame, FFT size, guard interval length, pilot pattern,etc.

Accordingly, the broadcast signal reception apparatus according to anembodiment of the present invention can identify the correspondingbroadcast system and frame type by detecting the preamble of the signalframe first and selectively receive and decode a broadcast signalcorresponding to receiver type.

That is, even when a broadcast signal in which frames including variousbroadcast services such as UHD, mobile and MISO/MIMSO services aremultiplexed is received through the one RF, the broadcast signalreception apparatus according to an embodiment of the present inventioncan obtain information of the corresponding frames by decoding preamblesof the frames.

Edge symbols may be located after the preamble of each signal frame orat the end of each signal frame. Names, positions and number of edgesymbols may be changed according to designer. Edge symbols may beinserted into each signal frame to support freedom of preamble designand multiplexing of signal frames of different types. An edge symbol mayinclude a larger number of pilots than a data symbol to enablefrequency-only interpolation and time interpolation between datasymbols. Accordingly, a pilot pattern of the edge symbol has higherdensity than a data symbol pilot pattern.

The signaling field is a field for transmitting the aforementioned PLSdata and may include additional system information (networktopology/configuration, PAPR use and the like) and frame typeUD/configuration information and information necessary to extract anddecode each DP.

A data symbol is used to transmit DP data. The aforementioned cellmapper can arrange a plurality of DPs in the data symbol.

The present invention suggests a normal preamble and a robust preambleas a preamble structure in the time domain and frequency domain and amethod for signaling an EAS related signal through a preamble.

The broadcast signal transmission apparatus according to an embodimentof the present invention may insert a preamble structure depending on atarget SNR of a service to be provided into a signal frame. The robustpreamble according to an embodiment of the present invention, which willbe described later, has excellent detection performance even in a lowSNR environment but may generate unnecessary overhead in a receiversince an FFT size and guard interval increase. Accordingly, thebroadcast signal transmission apparatus according to an embodiment ofthe present invention can insert the normal preamble into a signal frametransmitted in a high SNR environment and insert the robust preambleinto a signal frame transmitted in a low SNR environment.

The above-described three profiles can be defined as broadcast signaltransmission/reception scenarios for providing services corresponding todifferent reception environments. Accordingly, the broadcast signaltransmission apparatus according to an embodiment of the presentinvention can insert the normal preamble or the robust preambleaccording to a profile transmitted through a signal frame.

A description will be given of generation processes, structures andsignaling information of the normal preamble and the robust preambleaccording to an embodiment of the present invention.

FIG. 31 illustrates a preamble insertion block according to anembodiment of the present invention.

FIG. 31 shows another embodiment of the preamble insertion block 7500described above. As shown in FIG. 31, the preamble insertion blockaccording to an embodiment of the present invention may include a ReedMuller encoder 17000, a data formatter 17010, a cyclic delay block17020, an interleaver 17030, a DQPSK (Differential Quadrature PhaseShift Keying)/DBPSK (Differential Binary Phase Shift Keying) mapper17040, a scrambler 17050, a carrier allocation block 17060, a carrierallocation table block 17070, an IFFT block 17080, a scrambled guardinsertion block 17090 and a multiplexing block 17100. Each block may bemodified according to designer or may not be included in the preambleinsertion block. A description will be given of operation of each block.

The Reed Muller encoder 17000 may receive signaling information to betransmitted through a preamble and perform Reed Muller encoding of theinput signaling information. When Reed Muller encoding is performed,signaling performance can be improved over conventional signaling usingan orthogonal sequence.

The data formatter 17010 may receive bits of the Reed-Muller-encodedsignaling information and perform formatting for repeating and arrangingthe input bits.

The DQPSK/DBPSK mapper 17040 may map the formatted signaling informationbits according to DBPSK or DQPSK and output the mapped signalinginformation.

When the DQPSK/DBPSK mapper 17040 maps the formatted signalinginformation bits according to DBPSK, the operation of the cyclic delayblock 17020 may be skipped. The interleaver 17030 may receive theformatted signaling information bits, frequency-interleave the formattedsignaling information bits and output interleaved data. In this case,the operation of the interleaver 17030 may be omitted according todesigner.

When the DQPSK/DBPSK mapper 17040 maps the formatted signalinginformation bits according to DQPSK, the data formatter 17010 may outputthe formatted signaling information bits to the interleaver 17030through a path I shown in FIG. 31. The cyclic delay block 17020 maycyclic-delay the formatted signaling information bits output from thedata formatter 17010 and then output the delayed signaling informationbits to the interleaver 17030 through a path Q shown in FIG. 31. Whencyclic Q-delay is performed, performance in a frequency selective fadingchannel is improved.

The interleaver 17030 may perform frequency interleaving on thesignaling information and cyclic Q-delayed signal information, inputthrough the path I and path Q, and output interleaved information. Inthis case, the operation of the interleaver 17030 may be omittedaccording to designer.

The scrambler 17050 may receive the mapped signaling information outputfrom the DQPSK/DBPSK mapper 17040 and multiply the signaling informationby a scrambling sequence.

The carrier allocation block 17060 may arrange the signaling informationprocessed by the scrambler 17050 in a predetermined carrier positionusing position information output from the carrier allocation tableblock 17070.

The IFFT block 17080 may transform carriers output from the carrierallocation block 17060 into an OFDM signal of the time domain.

The scrambled guard insertion block 17090 may insert a scrambled guardinterval into the OFDM signal to generate a preamble. The scrambledguard insertion block 17090 according to an embodiment of the presentinvention may generate the scrambled guard interval by multiplying aguard interval in the form of a cyclic prefix by a scrambling sequence.The scrambled guard interval will be described later in detail. In thepresent invention, the scrambled guard interval can be referred to as ascrambled GI.

The scrambled guard insertion block 17090 may select the scramblingsequence according to whether an EAS message is inserted. The scrambledguard insertion block 17090 may determine whether to insert the EASmessage using EAS flag information that indicates whether the EASmessage is present in the preamble.

The multiplexing block 17100 may multiplex the output of the scrambledguard insertion block 17090 and a signal c(t) output from the guardsequence insertion block 7400 to output an output signal p(t). Theoutput signal p(t) may be input to the waveform processing block 7600described above.

The preamble insertion block according to an embodiment of the presentinvention can improve signaling performance over conventional signalingusing an orthogonal sequence by performing Reed Muller encoding andenhance performance in a frequency selective fading channel byperforming cyclic Q-delay.

FIG. 32 shows mathematical expressions representing relationshipsbetween input information and output information or mapping rules of theDQPSK/DBPSK mapper 17040 according to an embodiment of the presentinvention.

FIG. 32(a) shows mathematical expressions representing a relationshipbetween input information and output information or a mapping rule whenthe DQPSK/DBPSK mapper 17040 according to an embodiment of the presentinvention maps the input signaling information according to DBPSK.

FIG. 32(b) shows mathematical expressions representing a relationshipbetween input information and output information or a mapping rule whenthe DQPSK/DBPSK mapper 17040 according to an embodiment of the presentinvention maps the input signaling information according to DQPSK.

As shown in FIG. 32, the input information of the DQPSK/DBPSK mapper17040 may be represented as si[n] and sq[n] and the output informationof the DQPSK/DBPSK mapper 17040 may be represented as mi[n] and mq[n]for convenience of description.

FIG. 33 illustrates preamble structures according to an embodiment ofthe present invention.

FIG. 33(a) shows a structure of the normal preamble and FIG. 33(b) showsa structure of the robust preamble.

In the structure of the robust preamble according to an embodiment ofthe present invention, the normal preamble is repeated. Specifically, inthe robust preamble structure according to an embodiment of the presentinvention, the normal preamble is repeated twice. The robust preambleaccording to an embodiment of the present invention is designed todetect and decode the preamble symbol under harsh channel conditionslike mobile reception.

The normal preamble shown in FIG. 33(a) may be generated by the preambleinsertion block shown in FIG. 31. The robust preamble shown in FIG.33(b) may be generated by a preamble insertion block according to anembodiment of the present invention, shown in FIG. 34 or 21, which willbe described later.

The normal preamble according to an embodiment of the present inventionmay include a scrambled GI region and an OFDM data region. The scrambledGI region of the preamble according to an embodiment of the presentinvention may be a scrambled cyclic postfix or a scrambled cyclicprefix. The scrambled cyclic postfix may be located after an OFDMsymbol, distinguished from a scrambled prefix and may be generatedthrough the same process as used to generate the scrambled cyclicprefix, which will be described later. The process of generating thescrambled cyclic postfix may be modified according to designer.

The scrambled GI region shown in FIG. 33 may be generated by scramblingsome or all OFDM symbols and used as a guard interval. The scrambled GIand OFDM data of the normal preamble according to an embodiment of thepresent invention may have the same length. In FIG. 33, the scrambled GIand OFDM data have a length of N and the normal preamble has a length of2N. N, which relates to the length of the preamble according to anembodiment of the present invention, may refer to an FFT size.

The preamble according to an embodiment of the present invention iscomposed of 3 signaling fields, namely S1, S2 and S3. Each signalingfield contains 7 signaling bits, and the preamble carries 21 signalingbits in total. Each signaling field is encoded with a first-order ReedMuller (64, 7) code.

The signaling fields according to an embodiment of the present inventionmay include the aforementioned signaling information. The signalingfields will be described in detail later.

The broadcast signal reception apparatus according to an embodiment ofthe present invention can detect a preamble through guard intervalcorrelation using a guard interval in the form of a cyclic prefix evenwhen frequency synchronization cannot be performed.

In addition, the guard interval in the form of a scrambled cyclic prefixaccording to an embodiment of the present invention can be generated bymultiplying (or combining) an OFDM symbol by (or with) a scramblingsequence (or sequence). Furthermore, the guard interval in the form of ascrambled cyclic prefix according to an embodiment of the presentinvention can be generated by scrambling the OFDM symbol and thescrambling sequence. The scrambling sequence according to an embodimentof the present invention can be any type of signal according todesigner.

The method of generating the guard interval in the form of a scrambledcyclic prefix according to an embodiment of the present invention hasthe following advantages.

Firstly, the preamble can be easily detected by discriminating thepreamble from the normal OFDM symbol. The guard interval in the form ofa scrambled cyclic prefix is generated through scrambling using thescrambling sequence, distinguished from the normal OFDM symbol, asdescribed above. In this case, when the broadcast signal receptionapparatus according to an embodiment of the present invention performsguard interval correlation, the preamble can be easily detected since acorrelation peak according to the normal OFDM symbol is not generatedand only a correlation peak according to the preamble is generated.

Secondly, when the guard interval in the form of a scrambled cyclicprefix according to an embodiment of the present invention is used,dangerous delay can be prevented. For example, when multipathinterference having a delay corresponding to an OFDM symbol period Tuexists, since a correlation value according to multiple paths is presentall the time when the broadcast signal reception apparatus performsguard interval correlation, preamble detection performance may bedeteriorated. However, when the broadcast signal reception apparatusaccording to an embodiment of the present invention performs guardinterval correlation, the preamble can be detected without beingaffected by a correlation value according to multiple paths since only apeak according to the scrambled cyclic prefix is generated, as describedabove.

Finally, influence of continuous wave (CW) interference can beprevented. When a received signal includes CW interference, a DCcomponent according to CW is present all the time during guard intervalcorrelation performed by the broadcast signal reception apparatus andthus signal detection performance and synchronization performance of thebroadcast signal reception apparatus may be deteriorated. However, whenthe guard interval in the form of a scrambled cyclic prefix according toan embodiment of the present invention is used, the influence of CW canbe prevented since the DC component according to CW is averaged out bythe scrambling sequence.

(b) The robust preamble according to an embodiment of the presentinvention has repeated normal preambles, as shown in FIG. 33.Accordingly, the robust preamble may include the scrambled GI region andthe OFDM data region.

The robust preamble is a kind of repetition of the normal preamble, andcarries the same signaling fields S1, S2 and S3 with a differentsignaling scrambler sequence (SSS).

The first half of the robust preamble, shown in FIG. 33(b), is exactlythe same as the normal preamble. The second half of the robust preambleis a simple variation of the normal preamble where the difference arisesfrom the sequence SSS applied in the frequency domain. Accordingly, thesecond half of the robust preamble includes the same information as thatof the normal preamble but may have different data in the frequencydomain. In addition, OFDM data B has the same signaling data as OFDMdata A but may have a different output waveform in the time domain. Thatis, while inputs of the Reed Muller encoder 17000 for respectivelygenerating the first half of the robust preamble and the second half ofthe robust preamble are identical, the IFFT block 17080 may outputdifferent waveforms.

The doubled length of the robust preamble according to an embodiment ofthe present invention improves the detection performance in the timedomain, and the repetition of the signaling fields improves the decodingperformance for the preamble signaling data. The generation process ofthe robust preamble symbol is shown in FIG. 33. The detailed functionalsteps are described in the following description.

The signaling fields will be described in detail with reference to FIGS.24, 25 and 26 and the robust preamble generation process will bedescribed in detail with reference to FIGS. 20 and 21.

The robust preamble according to an embodiment of the present inventioncan be detected even by a normal reception apparatus in an environmenthaving a high SNR (Signal to Noise Ratio) since the robust preambleincludes the normal preamble structure. In an environment having a lowSNR, the robust preamble can be detected using the repeated structure.In FIG. 33(b), the robust preamble has a length of 4N.

When the broadcast signal reception apparatus according to an embodimentof the present invention receives a signal frame including the robustpreamble, the broadcast signal reception apparatus can stably detect thepreamble to decode signaling information even in a low SNR situation.

FIGS. 20 and 21 illustrate two methods for generating the robustpreamble according to an embodiment of the present invention. The robustpreamble structure according to an embodiment of the present inventionimproves the detection performance of signals of a broadcast receptionapparatus. The robust preamble may include structure of normal preamble.The robust preamble may additionally include repeated signaling datasame as the normal preamble. In this case, the signals of a broadcasttransmission apparatus according to an embodiment of the presentinvention can design differently repeated signaling data of waveformwhich is included the robust preamble in time domain than signaling dataof waveform which is included the normal preamble in time domain. Arobust preamble insertion block illustrated in FIG. 34 may generate therobust preamble by multiplying signaling information of the preamble bydifferent scrambling sequences in scramblers to output multiple piecesof scrambled signaling information and allocating the multiple pieces ofscrambled signaling information multiplied by the scrambling sequencesto OFDM symbol carriers on the basis of the same carrier allocationtable.

A robust preamble insertion block illustrated in FIG. 35 may generatethe robust preamble by multiplying preamble signaling information by thesame scrambling sequence and allocating the preamble signalinginformation multiplied by the scrambling sequence to OFDM symbolcarriers on the basis of different carrier allocation tables.

Detailed embodiments will now be described with reference to thefigures.

FIG. 34 illustrates a preamble insertion block according to anembodiment of the present invention.

Specifically, FIG. 34 shows another embodiment of the preamble insertionblock 7500 described above. The preamble insertion block shown in FIG.34 may generate the robust preamble. Referring to FIG. 34, the preambleinsertion block according to an embodiment of the present invention mayinclude a Reed Muller encoder 17000, a data formatter 17010, a cyclicdelay block 17020, an interleaver 17030, a DQPSK (DifferentialQuadrature Phase shift Keying)/DBPSK (Differential Binary Phase ShiftKeying) mapper 17040, a scrambler 17050, a carrier allocation block17060, a carrier allocation table block 17070, an IFFT block 17080, ascrambled guard insertion block 17090 and a multiplexing block 17100.Each block may be modified or may not be included in the preambleinsertion block according to designer. Operations of the blocks may bethe same as those of corresponding blocks shown in FIG. 31. Adescription will be given focusing on a difference between the robustpreamble generation process and the normal preamble generation process.

As described above, the robust preamble is composed of the first half ofthe robust preamble and the second half of the robust preamble and thefirst half of the robust preamble may be the same as the normalpreamble.

Robust preamble generation differs from normal preamble generation onlyby applying the sequence SSS in the frequency domain as described.Consequently, the Reed Muller encoder 17000, the data formatter 17010and the DQPSK/DBPSK mapper block 17040 are shared with the normalpreamble generation.

The first half of the robust preamble may be generated through the sameprocess as used to generate the normal preamble. In FIG. 34, OFDM data Aof the first half of the robust preamble may be generated by scramblingsignalling data input to the Reed Muller encoder 17000 through ascrambler A block 17050−1, a carrier allocation block 17060−1 and anIFFT module, allocating the scrambled data to active carriers andtransforming carriers output from the carrier allocation block 17060−1into an OFDM signal of the time domain.

OFDM data B of the second half of the robust preamble may be generatedby scrambling signalling data input to the Reed Muller encoder 17000through a scrambler B block 17050-2, a carrier allocation block 17060-2and an IFFT module, allocating the scrambled data to active carriers andtransforming carriers output from the carrier allocation block 17060-2into an OFDM signal of the time domain.

The carrier allocation blocks 17060−1 and 17060-2 according to anembodiment of the present invention can allocate the signaling data ofthe first half of the robust preamble and the signaling data of thesecond half of the robust preamble to carriers on the basis of the sameallocation table.

Scrambled guard insertion modules may respectively scramble OFDM data Aand OFDM data B respectively processed through the IFFT modules togenerate scrambled GI A and scrambled GI B, thereby generating the firsthalf of the robust preamble and the second half of the robust preamble.

FIG. 35 illustrates a preamble insertion block according to anembodiment of the present invention.

Specifically, FIG. 35 shows another embodiment of the preamble insertionblock 7500 described above. The preamble insertion block shown in FIG.34 may generate the robust preamble. Referring to FIG. 35, the preambleinsertion block according to an embodiment of the present invention mayinclude a Reed Muller encoder 17000, a data formatter 17010, a cyclicdelay block 17020, an interleaver 17030, a DQPSK (DifferentialQuadrature Phase shift Keying)/DBPSK (Differential Binary Phase ShiftKeying) mapper 17040, a scrambler 17050, a carrier allocation block17060, a carrier allocation table block 17070, an IFFT block 17080, ascrambled guard insertion block 17090 and a multiplexing block 17100.Each block may be modified or may not be included in the preambleinsertion block according to designer. Operations of the blocks may bethe same as those of corresponding blocks shown in FIG. 31.

A description will be given focusing on a difference between the robustpreamble generation process and the robust preamble generation processof FIG. 34.

The procedure of processing signaling data of the robust preambleaccording to an embodiment of the present invention through the ReedMuller encoder, data formatter, cyclic delay, interleaver, DQPSK/DBPSKmapper and scrambler modules may correspond to the aforementionedprocedure of processing the signaling data of the normal preamblethrough the respective modules.

The signaling data scrambled by the scrambler module may be input to acarrier allocation A module and a carrier allocation B module. Thesignaling information input to the carrier allocation A module and thecarrier allocation B module may be represented as p[n] (n being ainteger greater than 0). Here, p[n] may be represented as p[0] to p[N−1](N being the number of carriers to which all signaling information isallocated (or arranged). The carrier allocation A module and the carrierallocation B module may allocate (or arrange) the signaling informationp[n] to carriers on the basis of different carrier allocation tables.

For example, the carrier allocation A module can respectively allocatep[0], p[1] and p[N−1] to the first, second and N-th carriers. Thecarrier allocation B module can respectively allocate p[N−1], p[N−2],p[N−3] and p[0] to the first, second, third and N-th carriers.

The preamble insertion blocks illustrated in FIGS. 20 and 21 cangenerate the first half of the robust preamble and the second half ofthe robust preamble using different scrambling sequences or using thesame scrambling sequence and different carrier allocation schemes.Signal waveforms of the first half and the second half of the robustpreamble generated according to an embodiment of the present inventionmay differ from each other. Accordingly, data offset due to a multipathchannel is not generated even when the same signaling information isrepeatedly transmitted in the time domain.

FIG. 36 is a graph showing a scrambling sequence according to anembodiment of the present invention.

This graph shows a waveform of a binary chirp-like sequence. The binarychirp-like sequence is an embodiment of a signal that can be used as ascrambling sequence of the present invention. The binary chirp-likesequence is a sequence which is quantized such that the real part andimaginary part of each signal value respectively have only ‘1’ and ‘−1’.The binary chirp-like sequence shown in FIG. 36 is composed of aplurality of square waves having different periods and a sequence periodis 1024 according to an embodiment.

The binary chirp-like sequence has the following advantages. Firstly,the binary chirp-like sequence does not generate dangerous delay sincethe binary chirp-like sequence is composed of signals having differentperiods. Secondly, the binary chirp-like sequence provides correctsymbol timing information compared to conventional broadcast systemssince correlation characteristics are similar to those of guard intervalcorrelation and is resistant to noise on a multipath channel compared toa sequence having delta-like correlation such as an m-sequence. Thirdly,when scrambling is performed using the binary chirp-like sequence,bandwidth is less increased compared to the original signal. Fourthly,the binary chirp-like sequence is a binary sequence and thus can be usedto design a device having low complexity.

In the graph showing the waveform of the binary chirp-like sequence, thesolid line represents a waveform corresponding to a real part and adotted line represents an imaginary part. The waveforms of the real partand the imaginary part of the binary chirp-like sequence correspond tosquare waves.

FIG. 37 illustrates examples of scrambling sequences modified from thebinary chirp-like sequence according to an embodiment of the presentinvention.

FIG. 37(a) shows a reversed binary chirp-like sequence obtained byreversely arranging the binary chirp-like sequence in the time domain.

FIG. 37(b) shows a conjugated binary chirp-like sequence obtained bycomplex conjugating the binary chirp-like sequence. That is, the realpart of the conjugated binary chirp-like sequence equals the real partof the binary chirp-like sequence and the imaginary part of theconjugated binary chirp-like sequence equals the imaginary part of thebinary chirp-like sequence in terms of absolute value and is opposite tothe imaginary part of the binary chirp-like sequence in terms of sign.

FIG. 37(c) shows a cyclically-shifted binary chirp-like sequenceobtained by cyclically shifting the binary chirp-like sequence by a halfperiod, that is, 512.

FIG. 37(d) shows a half-negated sequence. A front half period, that is,0 to 512 of the half-negated chirp-like sequence equals that of thebinary chirp-like sequence and the real part and imaginary part of arear half period, that is, 513 to 1024 of the half-negated chirp-likesequence equals that of the binary chirp-like sequence in terms ofabsolute value and is opposite to the binary chirp-like sequence interms of sign.

The average of the above-described scrambling sequence is 0. Even when acontinuous wave interference is generated in a signal and thus a complexDC is present in an output of a differential decoder of the broadcastsignal reception apparatus, the scrambling sequence having an average of0 can be multiplied by the complex DC of the output of the differentialdecoder to prevent the complex DC from affecting signal detectionperformance.

The broadcast signal transmission apparatus according to an embodimentof the present invention can use the scrambling sequences shown in FIGS.22 and 23 differently according to whether the EAS message is includedin the preamble. For example, when the broadcast signal transmissionapparatus does not include the EAS message in the preamble, the guardinterval of the preamble can be scrambled using the scrambling sequenceof FIG. 36. When the broadcast signal transmission apparatus includesthe EAS message in the preamble, the guard interval of the preamble canbe scrambled using one of the scrambling sequences of FIG. 37.

The scrambling sequences shown in the figures are exemplary and may bemodified according to designer.

FIG. 38 illustrates a signaling information structure in the preambleaccording to an embodiment of the present invention.

Specifically, FIG. 38 shows the structure of signaling informationtransmitted through the preamble in the frequency domain according to anembodiment of the present invention.

FIGS. 24(a) and 24(b) illustrate repetition or arrangement of data bythe data formatter 17010 according to the length of a code block of ReedMuller encoding performed by the Reed Muller encoder 17000. The codeblock of Reed Muller encoding may be referred to as a Reed Muller FECblock.

The data formatter 17010 may repeat or arrange the signaling informationoutput from the Reed Muller encoder 17000 according to the length of thecode block such that the signaling information corresponds to the numberof active carriers. FIGS. 24(a) and (b) show an embodiment in which thenumber of active carriers is 384.

Accordingly, when the Reed Muller encoder 17000 performs Reed Mullerencoding on a 64-bit block, as shown in FIG. 38(a), the data formatter17010 can repeat the same data six times. In this case, the Reed Mullerencoder 17000 can use a 1^(st) order Reed Muller code and signalinginformation of each Reed Muller code may be 7 bits.

When the Reed Muller encoder 17000 performs Reed Muller encoding on a256-bit block, as shown in FIG. 38(b), the data formatter 17010 canrepeat front 128 bits or rear 128 bits of the 256-bit code block orrepeat even-numbered 128 bits or odd-numbered 128 bits of the 256-bitcode block to arrange data as 384 bits. In this case, the Reed Mullerencoder 17000 can use a 1^(st) order Reed Muller code and signalinginformation of each Reed Muller code may be 9 bits.

As described above, the signaling information formatted by the dataformatter 17010 may be processed through the cyclic delay block 17020and the interleaver 17030 or not, mapped through the DQPSK/DBPSK mapper17040, scrambled by the scrambler 17050 and then input to the carrierallocation block 17060.

FIG. 38(c) illustrates a method for allocating the signaling informationto active carriers through the carrier allocation block 17060 accordingto an embodiment of the present invention. In FIG. 38(c), b(n) (n beingan integer equal to or greater than 0) represents carriers to which datais allocated. In one embodiment, the number of carriers is 384. Coloredcarriers from among the carriers shown in FIG. 38(c) denote activecarriers and uncolored carriers denote null carriers. Positions of theactive carriers shown in FIG. 38(c) may be changed according todesigner.

FIG. 39 illustrates a procedure of processing signaling data transmittedthrough the preamble according to an embodiment of the presentinvention.

The signaling data transmitted through the preamble may include aplurality of signaling sequences. Each signaling sequence may be 7 bits.The number and size of the signaling sequences may be changed accordingto designer.

FIG. 39(a) shows a procedure of processing the signaling datatransmitted through the preamble when the signaling data is 14 bitsaccording to an embodiment of the present invention. In this case, thesignaling data transmitted through the preamble may include twosignaling sequences which may be referred to as signaling 1 andsignaling 2. Signaling 1 and signaling 2 may be the same signalingsequences as the aforementioned signaling sequences S1 and S2.

FIG. 39(b) shows a procedure of processing the signaling datatransmitted through the preamble when the signaling data is 21 bitsaccording to an embodiment of the present invention. In this case, thesignaling data transmitted through the preamble may include threesignaling sequences which may be referred to as signaling 1, signaling 2and signaling 3. Signaling 1, signaling 2 and signaling 3 may be thesame signaling sequences as the aforementioned signaling sequences S1,S2 and S3.

As shown in FIG. 39, the interleaving block 17030 according to anembodiment of the present invention may sequentially alternately assignS1 and S2 to active carriers.

The number of carriers is 384 and the carriers may be represented bysequential numerals starting from 0 in one embodiment. Accordingly, thefirst carrier according to an embodiment of the present invention can berepresented by b(0), as shown in FIG. 39). Uncolored active carriersshown in FIG. 39 denote null carriers to which S1, S2 or S3 is notarranged (or allocated).

A detailed description will be given of assignment of signalinginformation to signaling fields and active carriers.

Bit sequences of S1 and bit sequences of S2 according to an embodimentof the present invention are signaling sequences which may be allocatedto active carriers in order to transmit independent signalinginformation (or signaling fields) included in the preamble.

Specifically, S1 can carry 3-bit signaling information and can beconfigured in a structure in which a 64-bit sequence is repeated twice.In addition, S1 can be arranged before and after S2. S2 is a 256-bitsequence and can carry 4-bit signaling information. The bit sequences ofS1 and S2 of the present invention may be represented by sequentialnumerals starting from 0 according to one embodiment. Accordingly, thefirst bit sequence of S1 can be represented as S1(0) and the first bitsequence of S2 can be represented as S2(0). Representation of the bitsequences may be changed according to designer.

S1 may carry information for identifying each signal frame included inthe superframe described above with reference to FIG. 30, for example,information indicating an SISO-processed signal frame, MISO-processedsignal frame or FEF. S2 may carry information about an FFT size of thecurrent signal frame or information indicating whether framesmultiplexed in one superframe are of the same type. Information carriedthrough S2 may be changed according to designer.

Signaling 1 and signaling 2 may be respectively encoded into 64-bit ReedMuller codes by the aforementioned Reed Muller encoder. FIG. 39(a) showsa Reed-Muller-encoded signaling sequence block.

The encoded signaling sequence blocks of signaling 1 and signaling 2 maybe repeated three times by the aforementioned data formatter. FIG. 39(a)shows the repeated signaling sequence block of signaling 1 and therepeated signaling sequence block of signaling 2. Since theReed-Muller-encoded signaling sequence block is 64 bits, the signalingsequence block of each of signaling 1 and signaling 2, repeated threetimes, is 192 bits.

Data of signaling 1 and signaling 2, composed of 6 blocks, alternatelyrearranged, sequentially input to the cyclic delay block 17020 and theinterleaver 17030 and processed therein or mapped by the DBPSK/DQPSKmapper 17040 without undergoing processing of the cyclic delay block17020 and the interleaver 17030, and then allocated to 384 carriers bythe aforementioned carrier allocation block. In FIG. 39(a), b(0) maydenote the first carrier and b(1) and b(2) may denote carriers. In oneembodiment of the present invention, a total of 384 carriers b(0) tob(383) may be present. From among carriers shown in the figure, coloredcarriers denote active carriers and uncolored carriers denote nullcarriers. Active carriers represent carriers to which signaling data isallocated and null carriers represent carriers to which signaling datais not allocated. As described above, the data of signaling 1 andsignaling 2 may be alternately allocated to carriers. For example, dataof signaling 1 can be allocated to b(0), data of signaling 2 can beallocated to b(3) and data of signaling 1 can be allocated to b(7). Thepositions of the active carriers and null carriers may be changedaccording to designer.

(b) The signaling information transmitted through the preamble accordingto an embodiment of the present invention may be transmitted through thebit sequences of S1, bit sequences of S2 and bit sequences of S3.

S1, S2 and S3 according to an embodiment of the present invention aresignaling sequences which can be allocated to active carriers in orderto transmit independent signaling information (or signaling fields)included in the preamble.

Specifically, S1, S2 and S3 can respectively carry 3-bit signalinginformation and can be configured in a structure in which a 64-bitsequence is repeated twice. Accordingly, S1 , S2 and S3 can furthercarry 2-bit signaling information compared to the embodiment of FIG.39(b).

In addition, S1 and S2 can carry the signaling information describedwith reference to FIG. 39 and S3 can carry signaling information about aguard interval length (or guard length). Signaling information carriedthrough S1, S2 and S3 may be changed according to designer.

Data of signaling 1, signaling 2 and signaling 3, composed of 6 blocks,is alternately rearranged, sequentially input to the cyclic delay block17020 and the interleaver 17030 and processed thereby or mapped by theDBPSK/DQPSK mapper 17040 without undergoing processing of the cyclicdelay block 17020 and the interleaver 17030, and then allocated to 384carriers by the aforementioned carrier allocation block.

The bit sequences of S1, S2 and S3 may be represented by sequentialnumerals starting from 0, that is, m S1(0), . . . Referring to FIG.39(b), the number of carriers is 384 and the carriers may be representedby sequential numerals starting from 0, that is b(0), . . . according toone embodiment of the present invention. The number and representationmethod of the carriers may be changed according to designer.

Referring to FIG. 40, S1, S2 and S3 may be sequentially alternatelyallocated to active carriers in determined positions in the frequencydomain.

Specifically, the bit sequences of S1, S2 and S3 can be sequentiallyallocated to active carriers other than null carriers from among theactive carriers b(0) to b(383).

Each of signaling 1, signaling 2 and signaling 3 may be respectivelyencoded into a 64-bit Reed Muller code by the aforementioned Reed Mullerencoder. FIG. 40(b) shows a Reed-Muller-encoded signaling sequenceblock.

The encoded signaling sequence blocks of signaling 1, signaling 2 andsignaling 3 may be repeated twice by the aforementioned data formatter.FIG. 40(b) shows the repeated signaling sequence block of signaling 1,the repeated signaling sequence block of signaling 2 and the repeatedsignaling sequence block of signaling 3. Since each Reed-Muller-encodedsignaling block is 64 bits, the signaling sequence block of each ofsignaling 1, signaling 2 and signaling 3, repeated twice, is 128 bits.

Signaling 1, signaling 2 and signaling 3, composed of six blocks, may beallocated to 384 carriers by the aforementioned carrier allocationblock. In FIG. 40(b), b(0) may be the first carrier and b(1) and b(2)may be other carriers. In one embodiment, 384 carriers b(0) to b(383)may be present. Colored carriers from among the carriers shown in thefigure denote active carriers and uncolored carriers denote nullcarriers. Active carriers may be carriers to which signaling data isallocated and null carriers may be carriers to which signaling data isnot allocated. Data of signaling 1, signaling 2 and signaling 3 may bealternately allocated to carriers. For example, data of signaling 1 canbe allocated to b(0), data of signaling 2 can be allocated to b(1), dataof signaling 3 can be allocated to b(3) and data of signaling 1 can beallocated to b(7). The positions of the active carriers and nullcarriers shown in the figure may be changed according to designer.

FIG. 40 illustrates a procedure of processing signaling data transmittedthrough the preamble according to an embodiment of the presentinvention.

In FIG. 40(c) shows a procedure of processing signaling data transmittedthrough the preamble when the signaling data is 24 bits. In this case,the signaling data transmitted through the preamble may include threesignaling sequences which may be referred to as signaling 1, signaling 2and signaling 3. Signaling 1, signaling 2 and signaling 3 may be thesame signaling sequences as the aforementioned signaling information 51,S2 and S3. The procedure of processing the signaling data is the same asthe procedure described with reference to FIG. 39(b).

As described above with reference to FIGS. 25 and 26, a signaling datacapacity and a signaling data protection level can be traded off bycontrolling the length of an FEC-encoded signaling data block. That is,while the signaling data capacity increases as the length of thesignaling data block increases, the number of repetitions of the dataformatter decreases and the signaling data protection level is lowered.Accordingly, it is possible to select various signaling capacities.

Furthermore, the interleaver 17030 according to an embodiment of thepresent invention can uniformly interleave data of each signaling fieldin the frequency domain. Accordingly, frequency diversitycharacteristics of the preamble can be maximized and robustness againstfrequency selective fading can be improved.

FIG. 41 illustrates a differential encoding operation that can beperformed by a preamble insertion module according to an embodiment ofthe present invention.

The preamble insertion module according to an embodiment of the presentinvention may repeat signaling information (51, S2 and S3 represented assignaling 1, signaling 2 and signaling 3 in FIG. 41) twice. Then, thepreamble insertion module may sequentially alternately arrange repeatedbits of S1, S2 and S3. Alternatively, the data formatter according to anembodiment of the present invention may repeat and arrange the signalinginformation, as described above. Subsequently, the preamble insertionmodule may differential-encode consecutive bits (indicated by curvedarrows in the figure). Alternatively, the data formatter or DQPSK/DBPSKmapper according to an embodiment of the present invention maydifferential-encode the consecutive bits, as described above. Thepreamble insertion module may scramble the differentially encodedsignaling bits and sequentially alternately allocate the bits of S1, S2and S3 to corresponding carriers. Alternatively, the carrier allocationmodule according to an embodiment of the present invention may scramblethe differential encoded signaling bits and sequentially alternatelyallocate the bits of S1, S2 and S3 to the corresponding carriers.

FIG. 42 illustrates a differential encoding operation that can beperformed by a preamble insertion module according to another embodimentof the present invention.

Operations of the preamble insertion module according to the presentembodiment shown in FIG. 42 may correspond to the operations of thepreamble insertion modules shown in FIG. 41. In addition, operations ofthe data formatter, DQPSK/DBPSK mapper and carrier allocation modulewhich may be included in the preamble insertion module according to thepresent embodiment, shown in FIG. 42, may correspond to operations ofmodules which may be included in the preamble insertion module shown inFIG. 41.

However, order of the operations may be changed. Specifically, thepreamble insertion module according to the present embodiment may repeatsignaling information after differential encoding, distinguished fromthe operation of the preamble insertion module shown in FIG. 41. Thatis, the preamble insertion module can sequentially alternately arrangethe unrepeated bits of S1, S2 and S3. Then, the preamble insertionmodule can perform differential encoding of the arranged consecutivebits (indicated by curved arrows in the figure). Then, the preambleinsertion module may repeat the differentially encoded signaling bitsand sequentially alternately allocate the repeated bits to correspondingcarriers.

Operations of a signaling decoder of a preamble detector, which will bedescribed later, may depend on the order of differential encoding anddata repetition of the preamble insertion modules described withreference to FIGS. 27 and 28. Detailed operations of the signalingdecoder will be described later.

FIG. 43 is a block diagram of a correlation detector included in apreamble detector according to an embodiment of the present invention.

Specifically, FIG. 43 shows a configuration of the aforementionedpreamble detector 9300 according to one embodiment, that is, aconfiguration of a preamble correlation detector for detecting theaforementioned robust preamble.

The preamble correlation detector according to an embodiment of thepresent invention may include a normal preamble correlation detector(represented as a normal preamble detector in FIG. 43) and a robustpreamble correlation detector (represented as a robust preamble detectorin FIG. 43).

The robust preamble according to an embodiment of the present inventionmay have a structure in which the scrambled guard interval and dataregion are alternately arranged. The normal preamble correlationdetector may obtain correlation of the first half of the robustpreamble. The robust preamble correlation detector may obtaincorrelation of the second half of the robust preamble.

A description will be given of operation of the normal preamblecorrelation detector when the preamble received by the normal preamblecorrelation detector includes information related to the EAS message andthe broadcast signal transmission apparatus uses the binary chirp-likesequence of FIG. 36 and the half-negated sequence of FIG. 37(d) tosignal the information related to the EAS message through the preamble.

The normal preamble correlation detector may multiply signals (i) and(ii), obtained by delaying received signals (i) r(t) and (ii) r(t) by anFFT size, N, and conjugating the delayed signals, by each other.

The normal preamble correlation detector may generate the signal (ii) byconjugating r(t) and then delaying the conjugated r(t) by the FFT size,N. In FIG. 43, a block conj and a block ND (N Delay) can generate thesignal (ii).

A complex N/2 correlator may output correlation between the signalobtained by multiplying (i) by (ii) and a scrambling sequence. Asdescribed above, the first half period N/2 of the half-negated sequenceequals the first half period N/2 of the binary chirp-like sequence andthe sign of the second half period of the half-negated sequence isopposite to the sign of the second half period N/2 of the binarychirp-like sequence. Accordingly, the sum of outputs of two complex N/2correlators may be correlation with respect to the binary chirp-likesequence and a difference between the outputs of the two complex N/2correlators may be correlation with respect to the half-negatedsequence.

The robust preamble correlation detector may detect correlation on thebasis of the two sequence correlations detected by the normal preambledetector. The robust preamble correlation detector may detectcorrelation of the binary chirp-like sequence by summing (i) correlationdetected by the normal preamble detector and (ii) correlation obtainedby delaying a sequence detected by the normal preamble detector by 2N.

The robust preamble correlation detector can detect correlation bydelaying a sequence detected by the normal preamble detector by 2Ncorresponding to the length of OFDM data and scrambled GI since therobust preamble has a structure in which the OFDM data and scrambled GIare repeated twice.

Complex magnitude blocks of the normal preamble correlation detector andthe robust preamble correlation detector may output complex magnitudevalues of correlations detected through correlators. A peak detectorblock may detect a peak of complex magnitude values of inputcorrelations. The peak detector block may detect a preamble positionfrom the detected peak and perform OFDM symbol timing synchronizationand fractional frequency offset synchronization to output frame startinformation. In addition peak detector block may output informationabout preamble type, that is, the normal preamble or the robust preambleand information (EAS flag) about whether the preamble includes the EASmessage.

FIG. 44 illustrates a signaling decoder of a preamble detector accordingto an embodiment of the present invention.

Specifically, FIG. 44 shows an embodiment of the preamble detector 9300described above, which can perform a reverse of the operation of thepreamble insertion block shown in FIG. 31.

The preamble detector according to an embodiment of the presentinvention may include a correlation detector, an FFT block, an ICFOestimator, a carrier allocation table block, a data extractor and asignaling decoder. Each block may be modified according to designer ormay not be included in the preamble detector.

A description will be given of modules constituting the signalingdecoder and operations thereof.

The signaling decoder may include a descrambler 30000, an average block30010, a differential decoder 30020, a deinterleaver 30030, a cyclicdelay block 30040, an I/Q combiner 30050, a data deformatter 30060 and aReed Muller decoder 30070.

The descrambler 30010 may descramble received signaling data.

When the broadcast signal transmission apparatus repeats signalinginformation and then differential-encodes the repeated signalinginformation, as described with reference to FIG. 41, the average block30010 can be omitted. The differential decoder 30020 may receive thedescrambled signal and perform DBPSK or DQPSK demapping on thedescrambled signal.

Alternatively, when the broadcast signal transmission apparatusdifferential-encodes signaling information and then repeats thedifferential encoded signaling information, as described with referenceto FIG. 42, the average block 30010 may average corresponding symbols ofthe descrambled signaling data and then the differential decoder 30020may perform DBPSK or DQPSK demapping on the averaged signal. The averageblock may calculate a data average on the basis of the number ofrepetitions of the signaling information.

A description will be given of detailed operation of the differentialdecoder 30020.

When a transmitter receives a DQPSK-mapped signal, the differentialdecoder 30020 may perform phase rotation by π/4 on the differentialdecoded signal. Accordingly, the differential decoded signal can besegmented into in-phase and quadrature components.

When the transmitter has performed interleaving, the deinterleaver 30030may deinterleave the signal output from the differential decoder 30020.

When the transmitter has performed cyclic delay, the cyclic delay block30040 may perform a reverse of the cyclic delay operation performed inthe transmitter.

The I/Q combiner 30050 may combine I and Q components of thedeinterleaved signal or delayed signal.

When the signal received from the transmitter has been DBPSK mapped, theI/Q combiner 30050 can output only the I component of the deinterleavedsignal.

Then, the data deformatter 30060 may combine bits of signals output fromthe I/Q combiner 30050 per signaling field to output the signalinginformation. When the broadcast signal transmission apparatus repeatsthe signaling information and then differential encode the repeatedsignaling information, the data deformatter 30060 can average the bitsof the signaling information.

Subsequently, the Reed Muller decoder 30070 may decode the signalinginformation output from the data deformatter 30060.

Accordingly, the broadcast signal reception apparatus according to anembodiment of the present invention can obtain the signaling informationtransmitted using the preamble through the aforementioned procedure.

FIG. 45 illustrates a signaling decoder of a preamble detector accordingto an embodiment of the present invention.

Specifically, FIG. 45 shows an embodiment of the preamble detector 9300described above, which can perform a reverse of the operation of thepreamble insertion block shown in FIG. 34, that is, detect the robustpreamble.

The preamble detector according to an embodiment of the presentinvention may include a correlation detector, an FFT block, an ICFOestimator, a carrier allocation table block, a data extractor and asignaling decoder, as described above. Each block may be modifiedaccording to designer or may not be included in the preamble detector.

Modules constituting the signaling decoder and operations thereof willnow be described.

The signaling decoder may include a descrambler A, a descrambler B, anaverage block, a differential decoder, a deinterleaver, a cyclic delayblock, an I/Q combiner, a data deformatter and a Reed Muller decoder.

Operations of the descrambler A and descrambler B may correspond to theoperation of the aforementioned descrambler 30000.

Operations of other modules may correspond to operations of the modulesshown in FIG. 44.

The descrambler A and descrambler B according to an embodiment of thepresent invention may descramble OFDM data A and OFDM data B bymultiplying the OFDM data A and OFDM data B by a scrambling sequence.Then, the signaling decoder may sum descrambled data output from thedescrambler A and descrambler B. Subsequent operations of the signalingdecoder may be identical to corresponding operations of the signalingdecoder shown in FIG. 44.

FIG. 46 illustrates a signaling decoder of a preamble detector accordingto an embodiment of the present invention.

Specifically, FIG. 46 shows an embodiment of the preamble detector 9300described above, which can perform a reverse of the operation of thepreamble insertion block shown in FIG. 35, that is, detect the robustpreamble. The preamble detector according to an embodiment of thepresent invention may include a correlation detector, an FFT block, anICFO estimator, a carrier allocation table block, a data extractor and asignaling decoder. Each block may be modified according to designer ormay not be included in the preamble detector.

Modules constituting the signaling decoder and operations thereof willnow be described.

The signaling decoder may include a descrambler, an average block, adifferential decoder, a deinterleaver, a cyclic delay block, an I/Qcombiner, a data deformatter A, a data deformatter B and a Reed Mullerdecoder.

Operations of the data deformatter A and data deformatter B maycorrespond to the operation of the aforementioned data deformatter30060. Operations of the descrambler, average block, differentialdecoder, deinterleaver, cyclic delay block and I/Q combiner maycorrespond to the operations of the modules shown in FIG. 44.

Specifically, the data deformatter A and data deformatter B may combinesignaling information corresponding to OFDM data A or OFDM data B fromamong bits of signals output from the I/Q combiner per signaling fieldto output signaling information. Then, the signaling informationcombined per OFDM data output from the data deformatter A and datadeformatter B and per signaling field are combined and input to the ReedMuller decoder module. The Reed Muller decoder module may decode theinput signaling information.

FIG. 47 shows an OFDM generation block according to another embodimentof the present invention.

This invention may relate to preamble signaling for fast scan. Thepresent invention proposes that the FRU_CONFIGURE field be carried inthe preamble. Fast channel scan may be implemented by FRU_CONFIGURE. Thepresent invention may solve the disadvantage of the mixed flag that isconventionally used, enabling fast scan for any signal configuration.

Operation of the OFDM generation block according to another embodimentmay be similar to that of the OFDM generation block described in theprevious embodiment. In this embodiment, the OFDM generation block mayreceive signal frames output from the frame structure module describedabove, and demodulate and transmit the received signal frames accordingto the number of antennas outputting the signal frames.

According to another embodiment, the OFDM generation block may have mpaths. The data carried along the respective path may be transmittedthrough the m antennas.

According to another embodiment, the OFDM generation block may include areference signal insertion & PAPR reduction block, an inverse waveformtransform block, a PAPR reduction in time block, a guard sequenceinsertion block, a preamble insertion block, a waveform processingblock, an Other system insertion block and/or a digital analogconversion (DAC) block.

The reference signal insertion & PAPR reduction block may insert areference signal in a predetermined position of each signal block. Inaddition, this block may employ a PAPR reduction scheme to reduce thePAPR value in the time domain. In the case of an OFDM system, thereference signal insertion & PAPR reduction block may reserve someactive subcarriers rather than using them. The PAPR reduction operationmay be omitted in another embodiment.

The inverse waveform transform block may transform an input signal andoutput the transformed signal. In this case, transforming may beperformed in consideration of characteristics of the transmissionchannel. Transmission efficiency may be enhanced through this process.In the case of the OFDM system, the inverse waveform transform block mayconduct inverse fast Fourier transform (IFFT). In this case, the signalin the frequency domain may change to a signal in the time domain. Inthe case of an embodiment, particularly, a single carrier system, theinverse waveform transform block may be omitted.

The PAPR reduction in time block may perform the same operation as thePAPR reduction block. That is, the PAPR reduction block may decreasePAPR of an input signal in the time domain. In the case of the OFDMsystem, the PAPR reduction process may be a process of clipping the peakof a signal.

To minimize the influence of delay spread of the transmit channel, theguard sequence insertion block may set a guard interval between signalblocks. When necessary, it may insert a specific sequence between thesignal blocks. Accordingly, the receiver may easily performsynchronization or channel estimation. In the case of the OFDM system,the guard sequence insertion block may insert a cyclic prefix in theguard interval of an OFDM symbol.

The preamble insertion block may perform an operation similar to theoperation of the preamble insertion block described above. That is, thepreamble insertion block may insert a preamble in each signal toimplement fast detection of the signal. In this embodiment, the preambleinsertion block may perform preamble signaling for fast scan.

The waveform processing block may perform waveform processing accordingto the transmission characteristics of a channel. For example, thewaveform processing block may perform square-root-raised cosine (SRRC)filtering in order to obtain an out-of-band emission reference of atransmit signal. In the case of a multi-carrier system, the waveformprocessing block may be omitted.

The Other system insertion block may be the same as the Other systeminsertion block described above. That is, the Other system insertionblock may multiplex signals of a plurality of broadcasttransmission/reception systems in the time domain.

The DAC block may be the same as the DAC block previously described.That is, the DAC block may convert an input digital signal into ananalog signal and output the analog signal.

The blocks described above may be omitted or replaced with other blockshaving the same or similar function depending on the designer'sintention.

The operation related to preamble signaling for fast scan describedabove may be performed by the preamble insertion block. This is simplyillustrative, and the present invention may be performed by anotherblock, depending on the designer's intention, or may be performedthroughout a plurality of blocks.

FIG. 48 shows a synchronization & demodulation module according to oneembodiment of the present invention.

The preamble signaling for fast scan proposed in the present inventionmay be utilized by the receiver to implement fast scanning of channels.To this end, the receiver may detect a preamble according to anembodiment and utilize parsed information.

The synchronization & demodulation module according to this embodimentmay be a receive module corresponding to the OFDM generation block of aprevious embodiment. The synchronization & demodulation module accordingto this embodiment may receive a signal and demodulate the signal. Thatis, the synchronization & demodulation module according to thisembodiment may perform the reverse of the operation of the OFDMgeneration block of the previous embodiment.

The synchronization & demodulation module according to this embodimentmay include a tuner block, an ADC block, a preamble detector block, aguard sequence detector block, a waveform transform block, atime/frequency synchronization (sync) block, a reference signal detectorblock, a channel equalizer block, and/or an inverse waveform transformblock.

The tuner block may perform the operation of a typical tuner. That is,the tuner block may deliver a signal received from an antenna to thesystem. The analog-to-digital conversion (ADC) block may transform aninput analog signal to a digital signal.

The preamble detector block may correspond to the preamble insertionblock described above. The preamble detector block may obtain preamblesignaling information by detecting a preamble. To implement the fastscan proposed in the present invention, the signaled preamble may bedetected by the preamble detector block.

The guard sequence detector block may detect a guard sequence insertedby the transmitter. The information obtained by the guard sequencedetector block may be used for channel equalization in the channelequalizer block. The waveform transform block may function to transformthe input signal. This block may correspond to the waveform processingblock of the transmitter and reversely perform the operation of thewaveform processing block. The time/frequency sync block may performsynchronization of received signals in the time domain and the frequencydomain.

The reference signal detector may detect a reference signal inserted bythe transmitter. The reference signal detector block may detect thereference signal for the frequency domain. As described above, whentransmission is performed, a reference signal may be inserted in eachsignal. A data symbol in which the reference signal is inserted may bespecified by the designer. The receiver may detect the reference signalsand compensate the distortion of the signals by estimating the transmitchannel and the synchronization offset. The channel equalizer block mayfunction to synchronize the signals delivered through the transmitchannel. The inverse waveform transform block may correspond to theinverse waveform transform block of the transmitter, and reverselyperform the process.

The operation related to preamble signaling for fast scanning asdescribed above may be associated with the preamble detector blockshaded in the figure. According to this invention, the signaled preamblemay be detected by the preamble detector block. The signalinginformation of the detected preamble may be utilized to perform fastscanning of a channel.

FIG. 49 illustrates a signal frame and a preamble structure thereofaccording to the conventional art.

A signal frame according to the conventional art may include P1 symbol,L1-pre, L1-post, and payload. P1 symbol corresponding to the preamblemay include S1, S2 field1, and S2 field 2. L1-pre may containinformation for decoding L1-post. L1-post may include information fordecoding PLP of the payload. PLP containing desired data may be foundthrough L1-post. The payload region may contain actual data to betransmitted.

A receiver may detect the preamble, thereby recognizing the type of asignal frame. Herein, not only the type of the signal frame is signaled,but also the type of another signal frame for current transmission maybe signaled. In other words, the type of the preamble of another signalframe may also be signaled by the preamble for the current transmission.

The last bit of a 7-bit preamble may be allocated to S2 field 2. S2field 2 may function as a mixed flag. S2 field 2 may indicate whetherall preambles have a type identical to the current preamble type or apreamble of another type is transmitted in the current transmission.

If S2 field 2 is set to 0, all the preambles in the current transmissionmay be of the same type as that of the preamble of the correspondingsignal frame. If S2 field 2 is set to 1, at least one of the preamblessubject to the current transmission may be of a type different from thetype of the preamble of the corresponding signal frame.

In conventional cases, such mixed flag is signaled to assist thereceiver in performing fast scanning of channels.

FIG. 50 illustrates a conventional channel scanning process.

In describing the conventional channel scanning process, it is assumedthat a receiver to decode a T2-lite frame scans a channel. The T2-liteframe may be mixed and transmitted with T2 frames.

Herein, the T2 frame is a signal frame based on T2 technology. T2 mayrepresent a technology according to the second generation of theterrestrial digital video broadcasting (DVB) standard. T2-lite is asignal frame based on T2-lite technology. T2-lite, which is a subset ofT2, may represent an improved technology for mobile reception of T2.

The receiver may sequentially scan the system from channel 1 to channeln. The receiver may find, through channel scan, signal frames which thereceiver can receive.

Channel 1 is consists of T2 frames. Since this channel consists ofidentical frames, the mixed flag of the first T2 frame is set to 0.Accordingly, the receiver may decode only the first T2 frame, therebyrecognizing that none of the channels has a desired T2-lite frame. Thus,the receiver may start to scan channel 2.

Channel 2 may have a mixture of T2 frames and T2-lite frames.Accordingly, the mixed flags of the preambles of the frames constitutingchannel 2 may all be set to 1. When the receiver parses the preamble ofthe first T2 frame, it may recognize that there may be a T2-lite framein the channel since the mixed flag thereof is set to 1. Accordingly,the receiver may recognize that the system is not a system from which itcan receive information, but continue to decode the next frame. When thereceiver checks the T2-lite frame, it may start to scan the nextchannel.

Channel n consists only of T2-lite frames. Accordingly, the receiver mayrecognize that the channel is a receivable channel when it parses thefirst T2-lite frame. In this case, all the mixed flags of the preamblesin channel n may be set to 0.

When the mixed flag is used as above, the receiver may stop scanning ofa channel in which another system is present, and proceed to scan thenext channel.

FIG. 51 illustrates a problem of the conventional channel scanningprocess.

A problem may occur when the aforementioned T2-lite receiver scans achannel such as channel 3. Channel 3 is a channel in which T2 frames andNGH frames are present together.

Herein, the NGH frame may be a signal frame based on the NGH technology.NGH may stand for Next Generation Handheld, a broadcasting standard ofDVB.

Preambles of the frames of channel 3 may have mixed flags set to 1 sinceT2 frames and NGH frames are transmitted together.

In this case, the T2-lite receiver may initially decode a preamble of aT2 frame. Although the T2 frame is not the same system as that of theT2-lite receiver, the receiver may continue to decode the next frameassuming that there may be a T2-lite frame because the mixed flag of theT2 frame is set to 1.

The third frame is an NGH frame representing another system, decodingmay be continued since the mixed flag of the NGH frame is set to 1.

In the conventional cases of using the mixed flag as above, a receivermay limitlessly scan the system according to construction of a channel.This may lead to increase in scan time. For this reason, scanning mayneed to be set to be performed only for a certain time, or decoding mayneed to be set to be performed as long as the length of a superframe.

FIG. 52 illustrates a signal frame and a preamble structure thereofaccording to one embodiment of the present invention.

According to this embodiment, the signal frame may include a preamble,PLS1, PLS2 and/or a payload. PLS1, PLS2, and the payload are the same asthose described above.

The present invention proposes preamble signaling to address the problemof the conventional art as described above.

According to one embodiment of the present invention, the preamble mayinclude an FRU_CONFIGURE field. FRU_CONFIGURE may have a 3-bit value.With FRU_CONFIGURE, fast channel scan is possible, and the problemdescribed above may be solved.

In addition to FRU_CONFIGURE, the preamble may include the fields ofFFT_SIZE, GI_FRACTION, EAC_FLAG, PILOT_MODE, and PAPR_FLAG. Each fieldmay represent FFT size information, guard interval-related informationor emergency-related flag information. These fields have already beendescribed above.

FIG. 53 illustrates a signaling format of FRU_CONFIGURE of a preambleaccording to one embodiment of the present invention.

As previously described, configuration of a frame present in a channelmay be recognized through FRU_CONFIGURE. Herein, the range which can beindicated by FRU_CONFIGURE may be the whole channel or a superframe. Asdescribed above, if a superframe is constructed by repetition of a framerepetition unit (FRU), the FRUs having the same configuration may berepeated in a superframe, and therefore frame configuration of the FRUmay also be recognized through FRU_CONFIGURE.

As described above, PHY_PROFILE informs of the type of a frame havingthe preamble. That is, if PHY_PROFILE is set to 000, the frame may be aframe according to a base profile. If it is set to 001, the frame may bea frame according to a hand-held profile. If PHY_PROFILE is set to 010,the frame may be a frame according to an advanced profile. IfPHY_PROFILE is set to 111, the frame may be a future extension frame(FEF), namely, a frame for another system to be used in the future.

According to one embodiment, the FRU_CONFIGURE field may have 3 bits.Each bit may indicate whether or not a frame according to a specificprofile is present in the superframe.

To represent all configurations of a superframe with a small number ofbits, the FRU_CONFIGURE field indicates whether or not a frame accordingto a specific profile is present in the superframe in relation to thetype of a current frame. That is, configurations of the superframe maybe distinguished by combinations of FRU_CONFIGURE and PHY_PROFILE.

If FRU_CONFIGURE is set to 000, the channel or the superframe mayconsist of frames of one type which are not mixed with other types offrames. That is, if the profile of the current frame is a base profile(PHY_PROFILE=000), and the value of FRU_CONFIGURE is 000, only framesaccording to the base profile may be present in the superframe.

In the case in which the profile of the current frame is a base profile(PHY_PROFILE=000), if the first bit of FRU_CONFIGURE is set to 1, aframe according to the handheld profile may be present in thesuperframe. If the second bit of FRU_CONFIGURE is 1, a frame accordingto the advanced profile may be present in the superframe. If the thirdbit of FRU_CONFIGURE is 1, an FEF may be present in the superframe.

If the profile of the current frame is not the base profile, meaning ofeach bit of FRU_CONFIGURE may change. For example, in the case in whichthe profile of the current frame is the handheld profile(PHY_PROFILE=001), if the first bit of FRU_CONFIGURE is 1, a frameaccording to the base profile may be present in the superframe. If thesecond bit of FRU_CONFIGURE is 1, a frame according to the advancedprofile may be present in the superframe. If the third bit ofFRU_CONFIGURE is 1, an FEF may be present in the superframe.

For example, if the profile of the current frame is the advanced profile(PHY_PROFILE=010), and the value of FRU_CONFIGURE is 011, a frameaccording to the base profile is not present in the superframe, whereasa frame according to the handheld profile and an FEF are present in thesuperframe.

In this manner, all possible configurations that the superframe can havemay be represented. With the present invention, a large number ofsuperframe configurations may be represented with a smaller number ofbits through combination with the “current frame type indicating field:”(PHY_PROFILE). That is, the present invention implements efficientsignaling for a preamble with a limited number of bits, and providesminimum information allowing the receiver to implement fast channelscanning.

FIG. 54 illustrates a channel scanning process using preamble signalingaccording to one embodiment of the present invention.

For simplicity of description, the receiver is assumed to be a receivercapable of receiving a frame of the handheld profile. This receiversequentially scans the channels, starting with channel 1.

In the case of channel 1, only frames of the base profile and an FEF arepresent in the channel. The receiver parses the preamble of the frames.The receiver may recognize through PHY_PROFILE that the current frame isa frame of the base profile. In addition, the receiver may recognizethrough FRU_CONFIGURE that an FEF is present in this channel, but noneof the frames of the handheld and advanced profiles are present in thischannel. Accordingly, the receiver may stop decoding and start to scanthe next channel.

In the case of channel 2, frames of the base profile and handheldprofile and an FEF are present in the channel. The receiver mayrecognize, through PHY_PROFILE, that the current frame is a frame of thebase profile. In addition, the receiver may recognize throughFRU_CONFIGURE that frames of the handheld profile and an FEF are presentin this channel, but none of the frames of the advanced profiles arepresent in this channel. Accordingly, the receiver may continuedecoding.

In the case of channel 3, frames of the base profile and advancedprofile and an FEF are present in the channel. Channel 3 is a channelhaving a problem of the conventional art. The receiver may recognizethrough PHY_PROFILE that the current frame is a frame of the baseprofile. In addition, the receiver may recognize through FRU_CONFIGUREthat none of the frames of the handheld profile are present in thischannel. Accordingly, the receiver may proceed to scan the next channelwithout continuing decoding.

Through the preamble signaling as above, efficient signaling may beimplemented and the time taken to perform channel scanning may bereduced.

FIG. 55 illustrates preamble signaling according to one embodiment ofthe present invention.

The preamble of this embodiment may transmit 21-bit information asdescribed above. The preamble may include three signaling fields of S1,S2 and S3. Each signaling field may have the size of 7 bits.

The S1 field may include a 3-bit PHY_PROFILE field (m10, m11, m12), a3-bit FRU_CONFIGURE field (m13, m14, m15), and a 1-bit EAC_FLAG (m16)field.

The S2 field may include 2-bit FFT_SIZE field (m20, m21), a 3-bitGI_FRACTION field (m22, m23, m24), a 1-bit PILOT_MODE field (m25), and a1-bit PAPR_FLAG field (m26).

The S3 field may be reserved.

This configuration is simply illustrative, and data may be mapped to therespective bits of the preamble in a completely different manner.

Each signaling field may be encoded into a Reed-Muller codeword C, (i=1,2, 3). The equation given below describes the encoding process.C _(i) =m _(i) ×G={m _(i0) ,m _(i1) ,m _(i2) ,m _(i3) ,m _(i4) ,m _(i5),m _(i6) }×G={C _(i,0) , C _(i,1) , . . . ,C _(i,63)}  [Expression 12]

Each signaling field may be multiplied by the generator matrix G,thereby being encoded into a 64-bit Reed-Muller codeword.

FIG. 56 illustrates a method of transmitting broadcast signal accordingto an embodiment of the present invention.

The method includes demultiplexing input streams, encoding data of theeach PLPs (Physical Layer Pipes), building plural signal frames, and/ormodulating data by OFDM method & transmitting broadcast signals.

In step of demultiplexing input streams, the above described inputformatting module may process input streams. The input formatting modulecan process input streams into BB (Base Band) frames of PLPs. The inputformatting module can demultiplex input streams into PLPs.

In step of encoding data of the PLPs, the above described coding &modulation module may encode data of the each PLPs. The PLP can be alsoreferred to as DP. This step may include LDPC (Low Density Parity Check)encoding and/or bit interleaving. The data in in each data path can beencoded based on a code rate. Each PLPs can be encoded according to oneof the physical layer profiles. The physical layer profiles maycorrespond to Base profile, Handheld profile, and/or advanced profile,described above. Each physical layer profiles may be configurationsbased on reception condition. Each physical layer profiles can includeLDPC encoding and/or bit interleaving data of the PLP. The encoding withLDPC codes may correspond to LDPC encoding by LDPC encoder. The LDPCencoder may encode BB frames in the PLPs with LDPC codes. Bitinterleaving may correspond to bit interleaving by bit interleaver.

In step of building plural signal frames, the above-described framestructure module can build signal frames by mapping the encoded data ofthe each PLPs. Super frame can include at least two built signal frames.The super frame may correspond to the super frame described above.

In step of modulating data by OFDM method & transmitting broadcastsignals, the above-described waveform generation module can modulatedata in OFDM method, and transmit the broadcast signals.

In this embodiment, a preamble of the signal frame can include a firstsignal field indicating type of the current signal frame. The firstsignal field may correspond to PHY_PROFILE field, described above.

In a method of transmitting broadcast signals according to otherembodiment of the present invention, the preamble can further include asecond signal field indicating whether data encoded for fixed receptionare present in the current super frame, or not. The second signal fieldmay correspond to FRU_CONFIGURE field. The data encoded for fixedreception may correspond to data encoded according to Base profile. Thatis, the second signal field can indicate whether a signal frame of Baseprofile is included in a superframe.

In a method of transmitting broadcast signals according to anotherembodiment of the present invention, the preamble can further include asecond signal field indicating configuration of the physical layerprofiles of the signal frames in the super frame the second signal fieldmay correspond to FRU_CONFIGURE field. As described above, FRU_CONFIGUREfield can indicate PHY profile type configuration of the FRU that arepresent in the current super frame.

In a method of transmitting broadcast signals according to anotherembodiment of the present invention, value of the second signal fieldindicates whether a signal frame of certain physical layer profile ispresent in the super frame, in combination with value of the firstsignal field. The second signal field may correspond to FRU_CONFIGUREfield. And the first signal field may correspond to PHY_PROFILE field.Each bits of the FRU_CONFIGURE field can mean different thing based onthe value of the PHY_PROFILE field. That is, FRU_CONFIGURE field mayindicate presence of signal frame of certain PHY profile, in combinationwith value of the PHY_PROFILE field.

In a method of transmitting broadcast signals according to anotherembodiment of the present invention, the physical layer profiles includea first physical layer profile, a second physical layer profile, and athird physical layer profile. When the first signal field indicates thatthe current signal frame is a signal frame of the first physical layerprofile, first bit of the second signal field indicates whether a signalframe of the second physical layer profile is present in the superframe, second bit of the second signal field indicates whether a signalframe of the third physical layer profile is present in the super frame,and third bit of the second signal field indicates whether FEF (FutureExtension Frame) is present in the super frame. Here, the first physicallayer profile may correspond to Base profile. The second physical layerprofile may correspond to Handheld profile. The third physical layerprofile may correspond to Advanced profile. This may correspond tosecond column of table 8, described above.

In a method of transmitting broadcast signals according to anotherembodiment of the present invention, one of the physical layer profilefurther includes several processes. The processes are mapping the bitinterleaved data of the PLP onto constellations, MIMO (Multi Input MultiOutput) encoding the mapped data, and/or time interleaving the MIMOencoded data. Here, the one of the physical layer profile may correspondto Advanced profile, described above. The advanced profile can includeMIMO encoding process. The PLP being encoded according to the advancedprofile, can be encoded by MIMO scheme.

Mapping process may correspond to the constellation mapping conducted byconstellation mapper. MIMO encoding can refer to MIMO encoding performedby above described MIMO encoder. Time interleaving can correspond totime interleaving by time interleaver.

The above-described steps can be omitted or replaced by steps executingsimilar or identical functions according to design.

FIG. 57 illustrates a method of receiving broadcast signal according toan embodiment of the present invention.

The method includes receiving broadcast signals & demodulating data byOFDM method, parsing the plural signal frames, decoding the data of theeach PLPs, and/or multiplexing the decoded plural PLPs into outputstreams.

In step of receiving broadcast signals & demodulating data by OFDMmethod, the above-described synchronization & demodulation modulereceives broadcast signals, and demodulates data by OFDM method.

In step of parsing the plural signal frames, the above-described frameparsing module parses the signal frame by demapping data of plural PLPs.Super frame can include at least two built signal frames. The superframe may correspond to the super frame described above.

In step of decoding the data of the PLPs, the above-described demapping& decoding module decodes the PLP data. Step of decoding the PLP datacan include bit deinterleaving and/or LDPC decoding. Each PLPs can bedecoded according to one of the physical layer profiles. The physicallayer profiles may correspond to Base profile, Handheld profile, and/oradvanced profile, described above. Each physical layer profiles may beconfigurations based on reception condition. Each physical layerprofiles can include bit deinterleaving and/or LDPC decoding data of thePLP. In step of bit deinterleaving, the above-described bitdeinterleaver can conduct bit deinterleaving. In step of LDPC decoding.the above-described LDPC decoder(or FEC decoder) can decode PLP dataaccording to LDPC code, to output BB frames.

In step of multiplexing the decoded plural PLPs, the above describedoutput processor may conduct output processing on the BB frames of thePLPs. The output processor may output output streams.

In this embodiment, a preamble of the signal frame can include a firstsignal field indicating type of the current signal frame. The firstsignal field may correspond to PHY_PROFILE field, described above.

In a method of receiving broadcast signals according to other embodimentof the present invention, the preamble can further include a secondsignal field indicating whether data encoded for fixed reception arepresent in the current super frame, or not. The second signal field maycorrespond to FRU_CONFIGURE field. The data encoded for fixed receptionmay correspond to data encoded according to Base profile. That is, thesecond signal field can indicate whether a signal frame of Base profileis included in a superframe.

In a method of receiving broadcast signals according to anotherembodiment of the present invention, the preamble can further include asecond signal field indicating configuration of the physical layerprofiles of the signal frames in the super frame the second signal fieldmay correspond to FRU_CONFIGURE field. As described above, FRU_CONFIGUREfield can indicate PHY profile type configuration of the FRU that arepresent in the current super frame.

In a method of receiving broadcast signals according to anotherembodiment of the present invention, value of the second signal fieldindicates whether a signal frame of certain physical layer profile ispresent in the super frame, in combination with value of the firstsignal field. The second signal field may correspond to FRU_CONFIGUREfield. And the first signal field may correspond to PHY_PROFILE field.Each bits of the FRU_CONFIGURE field can mean different thing based onthe value of the PHY_PROFILE field. That is, FRU_CONFIGURE field mayindicate presence of signal frame of certain PHY profile, in combinationwith value of the PHY_PROFILE field.

In a method of receiving broadcast signals according to anotherembodiment of the present invention, the physical layer profiles includea first physical layer profile, a second physical layer profile, and athird physical layer profile. When the first signal field indicates thatthe current signal frame is a signal frame of the first physical layerprofile, first bit of the second signal field indicates whether a signalframe of the second physical layer profile is present in the superframe, second bit of the second signal field indicates whether a signalframe of the third physical layer profile is present in the super frame,and third bit of the second signal field indicates whether FEF (FutureExtension Frame) is present in the super frame. Here, the first physicallayer profile may correspond to Base profile. The second physical layerprofile may correspond to Handheld profile. The third physical layerprofile may correspond to Advanced profile. This may correspond tosecond column of table 8, described above.

In a method of receiving broadcast signals according to anotherembodiment of the present invention, one of the physical layer profilefurther includes several processes. The processes are timedeinterleaving, MIMO decoding, and/or demapping data fromconstellations. Here, the one of the physical layer profile maycorrespond to Advanced profile, described above. These processes areapplied to PLPs, being decoded according to Advanced profile.

In step of time deinterleaving, the above-described time deinterleavercan conduct time deinterleaving PLP data. In step of MIMO decoding, theabove-described MIMO decoder can conduct MIMO decoding PLP data. MIMOdecoding can be conducted by using MIMO matrix including MIMOcoefficient. MIMO coefficient can be used for adjusting power imbalance.In step of demapping from constellations, the above-describedconstellation demapper can conduct demapping. The demapping can beconducted on PLP data. The above-described steps can be omitted orreplaced by steps executing similar or identical functions according todesign.

Although the description of the present invention is explained withreference to each of the accompanying drawings for clarity, it ispossible to design new embodiment(s) by merging the embodiments shown inthe accompanying drawings with each other. And, if a recording mediumreadable by a computer, in which programs for executing the embodimentsmentioned in the foregoing description are recorded, is designed innecessity of those skilled in the art, it may belong to the scope of theappended claims and their equivalents.

An apparatus and method according to the present invention may benon-limited by the configurations and methods of the embodimentsmentioned in the foregoing description. And, the embodiments mentionedin the foregoing description can be configured in a manner of beingselectively combined with one another entirely or in part to enablevarious modifications.

In addition, a method according to the present invention can beimplemented with processor-readable codes in a processor-readablerecording medium provided to a network device. The processor-readablemedium may include all kinds of recording devices capable of storingdata readable by a processor. The processor-readable medium may includeone of ROM, RAM, CD-ROM, magnetic tapes, floppy discs, optical datastorage devices, and the like for example and also include such acarrier-wave type implementation as a transmission via Internet.Furthermore, as the processor-readable recording medium is distributedto a computer system connected via network, processor-readable codes canbe saved and executed according to a distributive system.

It will be appreciated by those skilled in the art that variousmodifications and variations can be made in the present inventionwithout departing from the spirit or scope of the inventions. Thus, itis intended that the present invention covers the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents.

Both apparatus and method inventions are mentioned in this specificationand descriptions of both of the apparatus and method inventions may becomplementarily applicable to each other.

Various embodiments have been described in the best mode for carryingout the invention.

The present invention is available in a series of broadcast signalprovision fields.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the present inventionwithout departing from the spirit or scope of the inventions. Thus, itis intended that the present invention covers the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents.

What is claimed is:
 1. A method of transmitting broadcast signals, themethod including: encoding service data of Physical Layer Pipes (PLPs);bit interleaving the encoded service data; building at least one signalframe including the bit interleaved service data; and modulating data inthe at least one signal frame by Orthogonal Frequency DivisionMultiplexing (OFDM) method; inserting a preamble at a beginning of eachof the at least one signal frame after the modulating step; andtransmitting the broadcast signals having the modulated data, whereinthe preamble includes information for a size of Fast Fourier Transform(FFT), a guard interval and a pilot mode, wherein the preamble includestwo OFDM symbols, and wherein each of the two OFDM symbols in thepreamble includes information for an emergency alert.
 2. The method ofclaim 1, wherein the two OFDM symbols in the preamble include differentdata in a frequency domain, respectively.
 3. The method of claim 1,wherein each of the two OFDM symbols in the preamble includes differentdata in a time domain, respectively.
 4. The method of claim 1, whereinvalues used for the preamble is modulated to output a modulatedsequence.
 5. The method of claim 4, wherein the modulated sequence ismapped into active carriers at Inverse Fast Fourier Transform (IFFT)inputs of an OFDM scheme to output a time domain sequence.
 6. Anapparatus for transmitting broadcast signals, the apparatus including: aprocessor that encodes service data of Physical Layer Pipes (PLPs); bitinterleavebit interleaves the encoded service data; builds at least onesignal frame including the bit interleaved service data; and modulatesdata in the at least one signal frame by Orthogonal Frequency DivisionMultiplexing (OFDM) method; inserts a preamble at a beginning of each ofthe at least one signal frame after the data is modulated; and transmitsthe broadcast signals having the modulated data, wherein the preambleincludes information for a size of Fast Fourier Transform (FFT), a guardinterval and a pilot mode, wherein the preamble includes two OFDMsymbols, and wherein each of the two OFDM symbols in the preambleincludes information for an emergency alert.
 7. The apparatus of claim6, wherein the two OFDM symbols in the preamble include different datain a frequency domain, respectively.
 8. The apparatus of claim 6,wherein each of the two OFDM symbols in the preamble includes differentdata in a time domain, respectively.
 9. The apparatus of claim 6,wherein values used for the preamble is modulated to output a modulatedsequence.
 10. The apparatus of claim 9, wherein the modulated sequenceis mapped into active carriers at Inverse Fast Fourier Transform (IFFT)inputs of an OFDM scheme to output a time domain sequence.